Boise Cascade (BCC) 10-K 22 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 12, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-35805
Entity Registrant Name	Boise Cascade Company
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-1496201
Entity Address, Address Line One	1111 West Jefferson Street
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Boise
Entity Address, State or Province	ID
Entity Address, Postal Zip Code	83702-5389
City Area Code	208
Local Phone Number	384-6161
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	BCC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,462
Entity Common Stock, Shares Outstanding		39,202,927
Documents Incorporated by Reference [Text Block]	Portions of the registrant’s Proxy Statement for its 2021 annual meeting of stockholders are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0001328581
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Sales
Sales	$ 5,474,838	$ 4,643,404	$ 4,995,290
Costs and expenses
Materials, labor, and other operating expenses (excluding depreciation)	4,536,051	3,965,776	4,307,594
Depreciation and amortization	95,169	80,141	146,837
Selling and distribution expenses	428,279	390,739	363,138
General and administrative expenses	78,636	71,072	68,811
Loss on sale and curtailment of facilities	1,707	0	38,314
Other (income) expense, net	(33)	(783)	(1,442)
Total costs and expenses	5,139,809	4,506,945	4,923,252
Income from operations	335,029	136,459	72,038
Foreign currency exchange gain (loss)	357	449	(944)
Pension expense (excluding service costs)	(7,457)	(2,474)	(24,999)
Interest expense	(26,223)	(26,051)	(26,193)
Interest income	999	2,811	1,649
Change in fair value of interest rate swaps	(2,426)	(2,963)	551
Loss on extinguishment of debt	(13,968)	0	0
Total nonoperating income (expense)	(48,718)	(28,228)	(49,936)
Income before income taxes	286,311	108,231	22,102
Income tax provision	(111,332)	(27,306)	(1,625)
Net Income	$ 174,979	$ 80,925	$ 20,477
Weighted average common shares outstanding:
Basic (in shares)	39,277	39,039	38,932
Diluted (in shares)	39,431	39,242	39,387
Net income per common share:
Basic (in dollars per share)	$ 4.45	$ 2.07	$ 0.53
Diluted (in dollars per share)	4.44	2.06	0.52
Dividends declared per common share	$ 2	$ 1.37	$ 1.30

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 174,979	$ 80,925	$ 20,477
Defined benefit pension plans
Actuarial gain (loss), net of tax	5,104	(3,466)	10,580
Amortization of actuarial (gain) loss, net of tax	603	(131)	1,117
Effects of Settlements, net of tax	4,669	1,001	17,353
Stranded tax effects of pension plan termination	38,794	0	0
Other comprehensive income (loss), net of tax	49,170	(2,596)	29,050
Comprehensive income	$ 224,149	$ 78,329	$ 49,527

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income Parenthetical - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Actuarial gain (loss), tax	$ 1,728	$ (1,176)	$ 3,598
Amortization of actuarial (gain) loss, tax	204	(44)	380
Effects of settlements, tax effect	$ 1,581	$ 341	$ 5,902

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current
Cash and cash equivalents	$ 405,382	$ 285,237
Receivables
Trade, less allowances	375,865	215,894
Related parties	201	568
Other	15,067	15,184
Inventories	503,480	497,596
Prepaid expenses and other	8,860	8,285
Total current assets	1,308,855	1,022,764
Property and equipment, net	461,456	476,949
Operating lease right-of-use assets	62,447	64,228
Finance lease right-of-use assets	29,523	21,798
Timber deposits	11,761	12,287
Goodwill	60,382	60,382
Intangible assets, net	16,574	17,797
Deferred income taxes	7,460	7,952
Other assets	7,260	9,194
Total assets	1,965,718	1,693,351
Accounts payable
Trade	307,653	222,930
Related parties	1,199	1,624
Accrued liabilities
Compensation and benefits	118,400	83,943
Income taxes payable	8,101	0
Interest payable	8,477	6,723
Other	80,172	69,772
Total current liabilities	524,002	384,992
Debt
Long-term debt	443,792	440,544
Other
Compensation and benefits	25,951	45,586
Operating lease liabilities, net of current portion	56,001	58,029
Finance lease liabilities, net of current portion	31,607	23,419
Deferred income taxes	18,263	26,694
Other long-term liabilities	15,303	12,757
Total other liabilities	147,125	166,485
Commitments and contingent liabilities
Stockholders' equity
Preferred Stock, Value, Issued	$ 0	$ 0
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common Stock, Value, Issued	$ 446	$ 444
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	44,568,299	44,352,778
Treasury Stock, Common, Value	$ (138,909)	$ (138,909)
Treasury stock, shares at cost	5,367,000	5,367,000
Additional paid-in capital	$ 538,006	$ 533,345
Accumulated other comprehensive loss	(1,078)	(50,248)
Retained earnings	452,334	356,698
Total stockholders' equity	850,799	701,330
Total liabilities and stockholders' equity	$ 1,965,718	$ 1,693,351

Consolidated Balance Sheets Par

Consolidated Balance Sheets Parenthetical - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 1,111	$ 591

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash provided by (used for) operations
Net Income	$ 174,979	$ 80,925	$ 20,477
Items in net income not using (providing) cash
Depreciation and amortization, including deferred financing costs and other	97,131	82,377	148,937
Stock-based compensation	7,820	7,973	8,831
Pension expense	8,125	3,121	25,793
Deferred income taxes	27,497	9,025	(7,965)
Change in fair value of interest rate swaps	2,426	2,963	(551)
Loss on sale and curtailment of facilities (excluding severance)	1,476	0	37,331
Other	169	(353)	(1,688)
Loss on Extinguishment of Debt	13,968	0	0
Decrease (increase) in working capital, net of acquisitions
Receivables	(159,906)	2,160	37,561
Inventories	(6,249)	40,176	(64,190)
Prepaid expenses and other	(1,133)	(132)	(500)
Accounts payable and accrued liabilities	131,541	5,212	(14,531)
Pension contributions	(12,759)	(5,238)	(26,081)
Income taxes payable	9,022	19,387	(4,186)
Other	409	(1,949)	4,373
Net cash provided by operations	294,516	245,647	163,611
Cash provided by (used for) investment
Expenditures for property and equipment	(79,429)	(82,720)	(79,987)
Acquisitions of businesses and facilities	0	(15,676)	(25,482)
Proceeds from sale of facilities	0	2,493	15,003
Proceeds from sales of assets and other	713	1,838	1,209
Net cash used for investment	(78,716)	(94,065)	(89,257)
Cash provided by (used for) financing
Borrowings of long-term debt, including revolving credit facility	400,000	5,500	7,500
Payments of long-term debt, including revolving credit facility	(405,774)	(5,500)	(7,500)
Dividends paid on common stock	(79,195)	(53,954)	(50,615)
Tax withholding payments for stock-based awards	(3,309)	(3,574)	(5,135)
Payments of deferred financing costs	(6,222)	0	0
Treasury stock purchased	0	0	(4,930)
Other	(1,155)	(488)	857
Net cash used for financing	(95,655)	(58,016)	(59,823)
Net increase in cash and cash equivalents	120,145	93,566	14,531
Balance at beginning of the period	285,237	191,671	177,140
Balance at end of the period	$ 405,382	$ 285,237	$ 191,671

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]
Beginning balance, common stock, shares issued at Dec. 31, 2017		43,748,000
Beginning Balance, net of taxes at Dec. 31, 2017	$ 674,549	$ 437	$ (133,979)	$ 523,550	$ (76,702)	$ 361,243
Beginning balance, treasury stock shares at Dec. 31, 2017			5,167,000
Net Income	20,477					20,477
Other comprehensive income (loss)	29,050				29,050
Common stock issued, shares		328,000
Common stock issued, value	4	$ 4
Treasury stock, shares purchased			200,000
Treasury stock, value, acquired	(4,930)		$ (4,930)
Stock-based compensation	8,831			8,831
Common stock dividends	$ (51,664)					(51,664)
Dividends declared per common share	$ 1.30
Tax withholding payments on stock-based awards	$ (5,135)			(5,135)
Proceeds from exercise of stock options	1,412			1,412
Other	(4)			(4)		0
Ending balance, common stock, shares issued at Dec. 31, 2018		44,076,000
Ending Balance, net of taxes at Dec. 31, 2018	672,590	$ 441	$ (138,909)	528,654	(47,652)	330,056
Ending balance, treasury stock shares at Dec. 31, 2018			5,367,000
Net Income	80,925					80,925
Other comprehensive income (loss)	(2,596)				(2,596)
Common stock issued, shares		277,000
Common stock issued, value	3	$ 3
Stock-based compensation	7,973			7,973
Common stock dividends	$ (54,283)					(54,283)
Dividends declared per common share	$ 1.37
Tax withholding payments on stock-based awards	$ (3,574)			(3,574)
Proceeds from exercise of stock options	295			295
Other	$ (3)			(3)
Ending balance, common stock, shares issued at Dec. 31, 2019	44,352,778	44,353,000
Ending Balance, net of taxes at Dec. 31, 2019	$ 701,330	$ 444	$ (138,909)	533,345	(50,248)	356,698
Ending balance, treasury stock shares at Dec. 31, 2019	5,367,000		5,367,000
Net Income	$ 174,979					174,979
Other comprehensive income (loss)	49,170				49,170
Common stock issued, shares		215,000
Common stock issued, value	2	$ 2
Stock-based compensation	7,820			7,820
Common stock dividends	$ (79,343)					(79,343)
Dividends declared per common share	$ 2
Tax withholding payments on stock-based awards	$ (3,309)			(3,309)
Proceeds from exercise of stock options	152			152
Other	$ (2)			(2)
Ending balance, common stock, shares issued at Dec. 31, 2020	44,568,299	44,568,000
Ending Balance, net of taxes at Dec. 31, 2020	$ 850,799	$ 446	$ (138,909)	$ 538,006	$ (1,078)	$ 452,334
Ending balance, treasury stock shares at Dec. 31, 2020	5,367,000		5,367,000

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation Boise Cascade Company is a building products company headquartered in Boise, Idaho. Our operations began on October 29, 2004 (inception), when we acquired the forest products assets of OfficeMax, Incorporated. As used in these consolidated financial statements, the terms "Boise Cascade," "we," and "our" refer to Boise Cascade Company and its consolidated subsidiaries. We are one of the largest producers of engineered wood products (EWP) and plywood in North America and a leading United States (U.S.) wholesale distributor of building products. We operate our business using two reportable segments: (1) Wood Products, which primarily manufactures EWP and plywood, and (2) Building Materials Distribution (BMD), which is a wholesale distributor of building materials. For more information, see Note 17, Segment Information.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements include the accounts of Boise Cascade and its subsidiaries. Intercompany balances and transactions have been eliminated. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible assets, and other long-lived assets; legal contingencies; guarantee obligations; indemnifications; assumptions used in retirement, medical, and workers' compensation benefits; assumptions used in the determination of right-of-use assets and related lease liabilities; stock-based compensation; fair value measurements; income taxes; and vendor and customer rebates, among others. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates resulting from continuing changes in the economic environment will be reflected in the consolidated financial statements in future periods. Revenue Recognition Revenues are recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. For additional information regarding our revenue recognition policies, see Note 3, Revenues. Cash and Cash Equivalents Cash equivalents consist of short-term investments that have a maturity of three months or less at the date of purchase. At December 31, 2020 and 2019, the majority of our cash and cash equivalents were invested in money market funds that are broadly diversified and invested in high-quality, short-duration securities, including commercial paper, certificates of deposit, U.S. government agency securities, and similar instruments. We have significant amounts of cash and cash equivalents that are in excess of federally insured limits. Though we have not experienced any losses on our cash and cash equivalents to date and we do not anticipate incurring any losses, we cannot be assured that we will not experience losses on our cash and cash equivalents. Trade Accounts Receivables and Allowance for Doubtful Accounts Trade accounts receivable are stated at the amount we expect to collect. Trade accounts receivable do not bear interest. We make ongoing estimates relating to the collectability of our accounts receivable and maintain a reserve for estimated losses resulting from the inability of our customers to meet their financial obligations to us. At December 31, 2020 and 2019, we had $1.1 million and $0.6 million, respectively, recorded as allowances for doubtful accounts. In determining the amount of the reserve and in order to manage credit risk, we consider our historical level of credit losses, customer concentrations, and current economic trends and monitor the creditworthiness of significant customers based on ongoing credit evaluations. Our sales are principally to customers in the building products industry located in the U.S. and Canada. A significant portion of our sales are concentrated with a relatively small number of customers. In 2020, our top ten customers represented approximately 42% of sales, with one customer accounting for approximately 11% of total sales. At December 31, 2020, receivables from two customers accounted for approximately 13% and 12% of total receivables. At December 31, 2019, receivables from these two customers accounted for approximately 14% and 12% of total receivables. No other customer accounted for 10% or more of total receivables. Adjustments to the valuation allowance are charged to income. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. Although we have not experienced material credit losses in recent years, our actual future losses from uncollectable accounts may differ materially from our current estimates. As additional information becomes known, we may change our estimates. In the event we determine that a change in the reserve is appropriate, we will record a charge to "Selling and distribution expenses" in our Consolidated Statements of Operations in the period we make such a determination. Fair Value Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy under GAAP gives the highest priority to quoted market prices (Level 1) and the lowest priority to unobservable inputs (Level 3). In general, and where applicable, we use quoted prices in active markets for identical assets or liabilities to determine fair value (Level 1). If quoted prices in active markets for identical assets or liabilities are not available to determine fair value, we use quoted prices for similar assets and liabilities or inputs that are observable either directly or indirectly (Level 2). If quoted prices for identical or similar assets are not available or are unobservable, we may use internally developed valuation models, whose inputs include bid prices, and third-party valuations utilizing underlying asset assumptions (Level 3). See Note 12, Retirement and Benefit Plans, for the fair value measurements of our defined benefit plans' assets. Financial Instruments Our financial instruments are cash and cash equivalents, accounts receivable, accounts payable, long-term debt, and interest rate swaps. Our cash is recorded at cost, which approximates fair value, and our cash equivalents are money market funds. As of December 31, 2020 and 2019, we held $371.8 million and $259.5 million, respectively, in money market funds that are measured at fair value on a recurring basis using Level 1 inputs. The recorded values of accounts receivable and accounts payable approximate fair values based on their short-term nature. At December 31, 2020 and 2019, the book value of our fixed-rate debt was $400.0 million and $350.0 million, respectively, and the fair value was estimated to be $432.0 million and $364.7 million, respectively. The difference between the book value and the fair value is derived from the difference between the period-end market interest rate and the stated rate of our fixed-rate, long-term debt. We estimated the fair value of our fixed-rate debt using quoted market prices of our debt in inactive markets (Level 2 inputs). The interest rate on our variable-rate debt is based on market conditions such as the London Interbank Offered Rate (LIBOR) or a base rate. Because the interest rate on the variable-rate debt is based on current market conditions, we believe that the estimated fair value of the outstanding balance on our variable-rate debt approximates book value. We are exposed to financial risks such as changes in commodity prices, interest rates, and foreign currency exchange rates. We employ a variety of practices to manage these risks, including operating and financing activities and, where deemed appropriate, the use of derivative instruments. As discussed in Note 16, Financial Instrument Risk, we use interest rate swaps to mitigate our variable interest rate exposure, the fair value of which is measured based on Level 2 inputs. Vendor Rebates and Allowances We receive rebates and allowances from our vendors under a number of different programs, including vendor marketing programs. At December 31, 2020 and 2019, we had $9.9 million and $9.2 million, respectively, of vendor rebates and allowances recorded in "Receivables, Other" on the Consolidated Balance Sheets. Rebates and allowances received from our vendors are recognized as a reduction of "Materials, labor, and other operating expenses (excluding depreciation)" when the product is sold, unless the rebates and allowances are linked to a specific incremental cost to sell a vendor's product. Amounts received from vendors that are linked to specific selling and distribution expenses are recognized as a reduction of "Selling and distribution expenses" in the period the expense is incurred. Foreign Currency The functional currency for our operations outside the United States is the U.S. dollar. Nonmonetary assets and liabilities and related depreciation and amortization for these foreign operations are remeasured into U.S. dollars using historical exchange rates. Monetary assets and liabilities are remeasured into U.S. dollars using the exchange rates as of the Consolidated Balance Sheet date. Revenue and expense items are remeasured into U.S. dollars using an average exchange rate prevailing during the year. Leases We primarily lease land, building, and equipment under operating and finance leases. We determine if an arrangement is a lease at inception and assess lease classification as either operating or finance at lease inception or upon modification. Substantially all of our leases with initial terms greater than one year are for real estate, including distribution centers, corporate headquarters, land, and other office space. Substantially all of these lease agreements have fixed payment terms based on the passage of time and are recorded in our Building Materials Distribution segment. Many of our leases include fixed escalation clauses, renewal options and/or termination options that are factored into our determination of lease term and lease payments when appropriate. Renewal options generally range from one to ten years with fixed payment terms similar to those in the original lease agreements. Some lease agreements provide us with the option to purchase the leased property at market value. Our lease agreements do not contain any residual value guarantees. Right-of-use (ROU) assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of fixed lease payments over the lease term. The current portion of our operating and finance lease liabilities are recorded in "Accrued liabilities, Other" on our Consolidated Balance Sheets. We use our estimated incremental borrowing rate, which is derived from information available at the lease commencement date, in determining the present value of lease payments. In determining our incremental borrowing rates, we give consideration to publicly available interest rates for instruments with similar characteristics, including credit rating, term, and collateralization. For purposes of determining straight-line rent expense, the lease term is calculated from the date we first take possession of the facility, including any periods of free rent and any renewal option periods we are reasonably certain of exercising. Variable lease expense generally includes reimbursement of actual costs for common area maintenance, property taxes, and insurance on leased real estate and are recorded as incurred. Most of our operating lease expense was recorded in "Selling and distribution expenses" in our Consolidated Statements of Operations. In addition, we do not separate lease and non-lease components for all of our leases. Our short-term leases primarily include equipment rentals with lease terms on a month-to-month basis, which provide for our seasonal needs and flexibility in the use of equipment. Our short-term leases also include certain real estate for which either party has the right to cancel upon providing notice of 30 to 90 days. We do not recognize ROU assets or lease liabilities for short-term leases. Income Taxes We account for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and respective tax bases and operating loss and tax credit carryforwards, as measured using enacted tax rates expected to be in effect in the periods where temporary differences are expected to be realized or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We recognize deferred tax assets to the extent that we believe that these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If we determine that we would be unable to realize our deferred tax assets in the future, we would make an adjustment to the deferred tax asset valuation allowance, which would increase the provision for income taxes. We review and update our tax positions as necessary to add any new uncertain tax positions taken, or to remove previously identified uncertain positions that have been adequately resolved. Additionally, uncertain positions may be remeasured as warranted by changes in facts or law. Accounting for uncertain tax positions requires estimating the amount, timing and likelihood of ultimate settlement. Although we believe that these estimates are reasonable, actual results could differ from these estimates. Inventory Valuation Inventories are valued at the lower of cost or net realizable value. Cost is based on the first-in, first-out (FIFO) method of inventory valuation or average cost. Wholesale distribution inventories include costs incurred in bringing inventory to its existing location. Manufactured inventories include costs for materials, labor, and factory overhead. Log inventories include costs to harvest and deliver the logs. Inventories included the following (work in process is not material): December 31, December 31, (thousands) Finished goods and work in process $ 431,663 $ 413,020 Logs 35,622 45,574 Other raw materials and supplies 36,195 39,002 $ 503,480 $ 497,596 Property and Equipment Property and equipment are recorded at cost. Cost includes expenditures for major improvements and replacements and the amount of interest cost associated with significant capital additions. For the years ended December 31, 2020, 2019, and 2018, an insignificant amount of interest was capitalized. We expense all repair and maintenance costs as incurred. When property and equipment are retired, sold, or otherwise disposed of, the asset's carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in income (loss). We use the straight-line method of depreciation. Property and equipment consisted of the following asset classes with the following general range of estimated useful lives: December 31, December 31, General Range of Estimated Useful Lives in Years (thousands) Land $ 47,099 $ 39,304 Buildings 151,718 140,008 20 - 40 Improvements 64,178 61,187 10 - 15 Mobile equipment, information technology, and office furniture 178,271 165,445 3 - 7 Machinery and equipment 687,768 666,467 7 - 12 Construction in progress 40,606 34,846 1,169,640 1,107,257 Less accumulated depreciation (708,184) (630,308) $ 461,456 $ 476,949 Long-Lived Asset Impairment We review long-lived assets for impairment when events or changes in circumstances indicate that the carrying amount of assets may not be recoverable (triggering event). An impairment of long-lived assets exists when the carrying value is not recoverable through future undiscounted cash flows from operations and when the carrying value of an asset or asset group exceeds its fair value. No triggering event was identified during the years ended December 31, 2020 and 2019. For a description of the impairment losses recorded during the year ended December 31, 2018, see Note 7, Sale of Manufacturing Facilities. Goodwill and Intangible Assets Impairment We maintain two reporting units for purposes of our goodwill impairment testing, Wood Products and Building Materials Distribution, which are the same as our operating segments discussed in Note 17, Segment Information. We test goodwill in each of our reporting units and intangible assets with indefinite lives for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. We also evaluate the remaining useful lives of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives are necessary. We completed our annual assessment of goodwill in fourth quarter 2020 using a qualitative approach. The qualitative goodwill impairment assessment requires evaluating factors, based on the weight of evidence, to determine whether a reporting unit's carrying value would more likely than not exceed its fair value. As part of our goodwill qualitative testing process for each reporting unit, we evaluate various factors that are specific to the reporting unit as well as industry and macroeconomic factors in order to determine whether they are reasonably likely to have a material impact on the fair value of our reporting units. Based on the qualitative analysis performed in 2020, we concluded that there were no changes that were reasonably likely to cause the fair value of the reporting units to be less than the reporting units' carrying value and determined that there was no impairment of our goodwill. In the event we were to determine that a reporting unit's carrying value would more likely than not exceed its fair value, quantitative testing would be performed comparing carrying values to estimated fair values. See Note 9, Goodwill and Intangible Assets, for additional information. Asset Retirement Obligations We recognize our asset retirement obligations in the period in which they are incurred if sufficient information is available to reasonably estimate the fair value of the obligation. Fair value estimates are determined using Level 3 inputs in the fair value hierarchy. The fair values of our asset retirement obligations are measured using expected future cash outflows discounted using the company's credit-adjusted risk-free interest rate. When we record the liability, we capitalize the cost by increasing the carrying amount of the related long-lived asset. Over time, the liability is accreted to its settlement value, and the capitalized cost is depreciated over the useful life of the related asset. Upon settlement of the liability, we will recognize a gain or loss for any difference between the settlement amount and the liability recorded. At December 31, 2020 and 2019, we had $2.3 million and $2.2 million, respectively, of asset retirement obligations recorded in "Other long-term liabilities" on our Consolidated Balance Sheets. These liabilities related primarily to landfill closure costs. The liabilities are based on the best estimate of current costs and are updated periodically to reflect current technology, laws and regulations, inflation, and other economic factors. We do not have any assets legally restricted for purposes of settling asset retirement obligations. We have additional asset retirement obligations with indeterminate settlement dates. The fair value of these asset retirement obligations cannot be estimated due to the lack of sufficient information to estimate the settlement dates of the obligations. These asset retirement obligations include, for example, (i) removal and disposal of potentially hazardous materials on equipment and/or an operating facility if the equipment and/or facility were to undergo major maintenance, renovation, or demolition; (ii) retention ponds that may be required to be drained and/or cleaned if the related operating facility is closed; and (iii) storage sites or owned facilities for which removal and/or disposal of chemicals and other related materials are required if the operating facility is closed. We will recognize a liability in the period in which sufficient information becomes available to reasonably estimate the fair value of these obligations. Pension Benefits Several estimates and assumptions are required to record pension costs and liabilities, including discount rates, expected return on plan assets, expected rate of compensation increases, retirement and mortality rates, expected contributions, and other factors. We review and update these assumptions annually unless a plan curtailment or other event occurs requiring that we update the estimates on an interim basis. See Note 12, Retirement and Benefit Plans, for additional information related to our pension plan. Deferred Software Costs We defer internal-use software costs that benefit future years. These costs are amortized using the straight-line method over the expected life of the software, typically three to five years. "Other assets" in the Consolidated Balance Sheets includes $4.1 million and $4.6 million, respectively, of deferred software costs at December 31, 2020 and 2019. During the year ended December 31, 2020, we amortized $1.9 million of deferred software costs. We amortized $2.0 million of deferred software costs for both of the years ended December 31, 2019 and 2018. Labor Concentration and Unions As of December 31, 2020, we had approximately 5,970 employees. Approximately 22% of these employees work pursuant to collective bargaining agreements. As of December 31, 2020, we had ten collective bargaining agreements. Two agreements covering approximately 740 employees at our Oakdale and Florien plywood plants are set to expire on July 15, 2021. If any of these agreements are not renewed or extended upon their termination, we could experience a material labor disruption, strike, or significantly increased labor costs at one or more of our facilities, either in the course of negotiations of a labor agreement or otherwise. Labor disruptions or shortages could prevent us from meeting customer demands or result in increased costs, thereby reducing our sales and profitability. Self-Insurance We are self-insured for certain losses related to workers' compensation and medical claims, general and auto liability, as well as property and business interruption losses. The expected ultimate costs for claims incurred are recognized as liabilities in the Consolidated Balance Sheets and are estimated based principally on an analysis of historical claims data and estimates of claims incurred but not reported. Losses are accrued and charged to operations when it is probable that a loss has been incurred and the amount can be reasonably estimated. We maintain third-party stop-loss insurance policies to cover these liability costs in excess of predetermined retained amounts. Costs related to the administration of the plans and related claims are expensed as incurred. At December 31, 2020 and 2019, self-insurance related liabilities of $9.5 million and $9.9 million, respectively, were classified within "Accrued liabilities," and $10.0 million and $10.0 million, respectively, were classified within "Other long-term liabilities" on our Consolidated Balance Sheets. New and Recently Adopted Accounting Standards In March 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting , which provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. Our current contracts that reference LIBOR include certain debt instruments and interest rate swaps. The amendments are effective for eligible contract modifications subsequent to March 12, 2020, and through December 31, 2022. The adoption of this standard did not have a material effect on our financial statements, but we will assess any eligible contract modifications in the future. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to reduce complexity in accounting for income taxes. This ASU removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The updated guidance is effective for interim and annual reporting periods beginning after December 15, 2020, with early adoption permitted. We adopted this standard in first quarter of 2021 and it did not have a material effect on our financial statements. In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans . This ASU amends ASC 715 to remove disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures, and adds disclosure requirements identified as relevant related to defined benefit pension and other postretirement plans. The ASU's changes related to disclosures are part of the FASB's disclosure framework project. The updated guidance is effective retrospectively for annual reporting periods ending after December 15, 2020, with early adoption permitted. We adopted this standard in fourth quarter of 2020 and it did not have a material effect on our financial statement disclosures. There were no other accounting standards recently issued that had or are expected to have a material impact on our consolidated financial statements and associated disclosures.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenues	Wood Products Segment Our Wood Products segment manufactures EWP, consisting of laminated veneer lumber (LVL), I-joists, and laminated beams, which are structural products used in applications where extra strength and consistent quality are required, such as headers and beams. LVL is also used in the manufacture of I-joists, which are assembled by combining a vertical web of oriented strand board (OSB) with top and bottom LVL or solid wood flanges. In addition, we manufacture structural, appearance, and industrial plywood panels, and ponderosa pine lumber. Our wood products are used primarily in new residential construction, residential repair-and-remodeling markets, and light commercial construction. The majority of our wood products are sold to leading wholesalers (including our Building Materials Distribution segment), home improvement centers, retail lumberyards, and industrial converters. For EWP, plywood and veneer, byproducts, and other products, we transfer control and recognize a sale when we ship the product from our manufacturing facility to our customer. Control transfers when product is shipped because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. The amount of consideration we receive and revenue we recognize varies with changes in rebates and cash discounts we offer to our customers. See "Rebates and Cash Discounts" below. Building Materials Distribution Segment Our Building Materials Distribution segment is a leading national stocking wholesale distributor of building materials. We distribute a broad line of building materials, including OSB, plywood, and lumber (collectively referred to as commodities); general line items such as siding, composite decking, doors, metal products, insulation, and roofing; and EWP. Except for EWP, we purchase most of these building materials from third-party suppliers and market them primarily to retail lumberyards, home improvement centers, and specialty distributors that then sell the products to the final end customers, who are typically homebuilders, independent contractors, and homeowners engaged in residential construction projects. Substantially all of Building Materials Distribution's EWP is sourced from our Wood Products segment. We sell products using two primary distribution methods: warehouse sales and direct sales. Warehouse sales are distributed from our warehouses to our customers. Direct sales are shipped from the manufacturer to the customer without us taking physical possession of inventory. We report direct sales on a gross basis, that is, the amounts billed to our customers are recorded as "Sales," and inventory purchased from manufacturers are recorded as "Materials, labor, and other operating expenses (excluding depreciation)." We are the principal of direct sales because we control the inventory, as we have the ability to direct its use before it is transferred to our customers. For warehouse sales, we transfer control and recognize a sale when the customer takes physical possession of the product. Control transfers when the customer takes physical possession of the product because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. For direct sales, we transfer control and recognize a sale when the product is shipped from the manufacturer to the customer. Control transfers when product is shipped because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. The amount of consideration we receive and revenue we recognize varies with changes in customer rebates and cash discounts we offer to our customers. See "Rebates and Cash Discounts" below. Rebates an d Cash Discounts Rebates are provided to our customers and our customers' customers based on the volume of their purchases, among other factors such as customer loyalty, conversion, and commitment. We provide the rebates to increase the sell-through of our products. Rebates are generally estimated based on the expected amount to be paid and recorded as a decrease in "Sales." At December 31, 2020 and 2019, we had $56.3 million and $49.4 million, respectively, of rebates payable to our customers recorded in "Accrued liabilities, Other" on our Consolidated Balance Sheets . We also estimate expected cash discounts on trade accounts receivable based on an analysis of historical experience and record cash discounts as a decrease in "Sales." We adjust our estimate of revenue at the earlier of when the probability of rebates paid and cash discounts provided ch anges or when the amounts become fixed. There have not been significant changes to our estimates of rebates, although it is reasonably possible that a change in the estimate may occur. Shipping and Handling Fees for shipping and handling charged to customers for sales transactions are included in "Sales" in our Consolidated Statements of Operations. When control over products has transferred to the customer, we have elected to recognize costs related to shipping and handling as fulfillment costs. For our Wood Products segment, costs related to shipping and handling are included in "Materials, labor, and other operating expenses (excluding depreciation)" in our Consolidated Statements of Operations. In our Wood Products segment, we view our shipping and handling costs as a cost of the manufacturing process and the movement of product to our end customers. For our Building Materials Distribution segment, costs related to shipping and handling of $177.1 million, $169.2 million, and $156.5 million for the years ended December 31, 2020, 2019, and 2018, respectively, are included in "Selling and distribution expenses" in our Consolidated Statements of Operations. In our Building Materials Distribution segment, our activities relate to the purchase and resale of finished product, and excluding shipping and handling costs from “Materials, labor, and other operating expenses (excluding depreciation)” provides us a clearer view of our operating performance and the effectiveness of our sales and purchasing functions. Other Our payment terms vary by the type of customer and the products offered. The term between invoicing and when payment is due is not significant. Sales, value add, and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. We expense sales commissions when incurred as they are earned. These costs are recorded within "Selling and distribution expenses."

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income Tax Provision Income before income taxes includes the following components: Year Ended December 31 2020 2019 2018 (thousands) Domestic $ 284,147 $ 105,341 $ 21,704 Foreign 2,164 2,890 398 Income before income taxes $ 286,311 $ 108,231 $ 22,102 The income tax provision shown in the Consolidated Statements of Operations includes the following: Year Ended December 31 2020 2019 2018 (thousands) Current income tax provision Federal $ 66,401 $ 13,700 $ 6,459 State 17,434 4,574 3,126 Foreign — 7 5 Total current 83,835 18,281 9,590 Deferred income tax provision (benefit) Federal 22,321 7,430 (5,987) State 4,529 925 (2,127) Foreign 647 670 149 Total deferred 27,497 9,025 (7,965) Income tax provision $ 111,332 $ 27,306 $ 1,625 The effective tax rate varies from the U.S. Federal statutory income tax rate principally due to the following: Year Ended December 31 2020 2019 2018 (thousands, except percentages) Income before income taxes $ 286,311 $ 108,231 $ 22,102 Statutory U.S. income tax rate 21.0 % 21.0 % 21.0 % Statutory tax provision $ 60,125 $ 22,728 $ 4,642 State taxes 12,267 4,390 741 Stranded tax effects of Plan Termination (a) 38,794 — — Unrecognized tax benefits 87 (178) (181) Benefit from enactment of the Tax Act (b) — — (3,806) Tax credits (712) (725) (272) Foreign rate differential 65 71 432 Share-based compensation (411) (532) (1,718) Nondeductible executive compensation 808 852 366 Meals and entertainment 340 738 886 Other (31) (38) 535 Total $ 111,332 $ 27,306 $ 1,625 Effective income tax rate 38.9 % 25.2 % 7.4 % ______________________________________ (a) In December 2020, we eliminated our qualified defined benefit pension plan (Plan Termination), as discussed in Note 12, Retirement and Benefit Plans. Prior to the Plan Termination, "Accumulated other comprehensive loss" on our Consolidated Balance Sheet included the stranded tax effects of our conversion from a limited liability company to a corporation in 2013 and the adoption of the Tax Cuts and Jobs Act (the "Tax Act") in 2017. Upon Plan Termination, these stranded tax effects of $38.8 million were required to be released into income tax expense under GAAP. (b) As of December 31, 2018, we completed our assessment of the effects of the Tax Act on our financial statements. In connection with our analysis of the Tax Act, we recorded a discrete tax benefit of $3.8 million during the year ended December 31, 2018. The $3.8 million reduction in income tax expense resulted from the remeasurement of deferred income taxes to the new federal statutory rate of 21%, which mostly related to a $20.0 million discretionary pension contribution made during 2018, for which we received a tax deduction at the 2017 federal income tax rate of 35%. During the year ended December 31, 2020, cash paid for taxes, net of refunds received, was $75.1 million. During the year ended December 31, 2019, income tax refunds received, net of cash taxes paid, was $1.4 million. During the year ended December 31, 2018, cash paid for taxes, net of refunds received, was $14.5 million. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. The components of our net deferred tax assets and liabilities at December 31, 2020 and 2019, are summarized as follows: December 31, 2020 December 31, 2019 (thousands) Deferred tax assets Employee benefits $ 29,258 $ 26,914 Lease liabilities 25,057 23,241 Inventories 3,711 3,358 Foreign net operating loss carryforward 1,279 1,514 Other 6,921 6,256 Deferred tax assets $ 66,226 $ 61,283 Deferred tax liabilities Property and equipment $ (45,652) $ (50,751) Right-of-use assets (23,256) (21,753) Intangible assets and other (6,823) (5,924) Other (1,298) (1,597) Deferred tax liabilities $ (77,029) $ (80,025) Total deferred tax liabilities, net $ (10,803) $ (18,742) As of December 31, 2020, we have foreign net operating loss carryforwards of $9.9 million, which if unused, will expire in years 2032 through 2036. We have state income tax credits totaling $1.3 million as of December 31, 2020, which if unused will expire in years 2021 through 2032. The foreign net operating loss and state credit carryforwards in the income tax returns filed included unrecognized tax benefits. The deferred tax assets recognized for those net operating loss and state credit carryforwards are presented net of these unrecognized tax benefits. Income Tax Uncertainties The following table summarizes the changes related to our gross unrecognized tax benefits excluding interest and penalties: 2020 2019 2018 (thousands) Balance as of January 1 $ 1,685 $ 1,850 $ 2,083 Increases related to prior years' tax positions 97 — 13 Increases related to current years' tax positions 89 53 — Decreases related to prior years' tax positions — — (43) Lapse of statute of limitations (91) (218) (203) Balance as of December 31 $ 1,780 $ 1,685 $ 1,850 As of December 31, 2020, 2019, and 2018, we had $1.8 million, $1.7 million, and $1.9 million, respectively, of unrecognized tax benefits recorded on our Consolidated Balance Sheets, excluding interest and penalties. Of the total unrecognized tax benefits recorded, $1.8 million, $1.7 million, and $1.8 million (net of the federal benefit for state taxes), respectively, would impact the effective tax rate if recognized. We recognize interest and penalties related to uncertain tax positions as income tax expense in our Consolidated Statements of Operations. For the years ended December 31, 2020, 2019, and 2018, we recognized an insignificant amount of interest and penalties related to taxes. We recognize tax liabilities and adjust these liabilities when our judgment changes as a result of the evaluation of new information not previously available or as new uncertainties occur. We do not expect the unrecognized tax benefits to change significantly over the next twelve months.

Net Income Per Common Share

Net Income Per Common Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Income Per Common Share	Net Income Per Common Share Basic net income per common share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Weighted average common shares outstanding for the basic net income per common share calculation includes certain vested restricted stock units (RSUs) and performance stock units (PSUs) as there are no conditions under which those shares will not be issued. For more information about common share activity during the period, see Note 14, Stockholders' Equity. Diluted net income per common share is computed by dividing net income by the combination of the weighted average number of common shares outstanding during the period and other potentially dilutive weighted average common shares. Other potentially dilutive weighted average common shares include the dilutive effect of stock options, RSUs, and PSUs for each period using the treasury stock method. Under the treasury stock method, the exercise price of a share and the amount of compensation expense, if any, for future service that has not yet been recognized are assumed to be used to repurchase shares in the current period. The following table sets forth the computation of basic and diluted net income per common share: Year Ended December 31 2020 2019 2018 (thousands, except per-share data) Net income $ 174,979 $ 80,925 $ 20,477 Weighted average common shares outstanding during the period (for basic calculation) 39,277 39,039 38,932 Dilutive effect of other potential common shares 154 203 455 Weighted average common shares and potential common shares (for diluted calculation) 39,431 39,242 39,387 Net income per common share - Basic $ 4.45 $ 2.07 $ 0.53 Net income per common share - Diluted $ 4.44 $ 2.06 $ 0.52

Curtailment of Manufacturing Fa

Curtailment of Manufacturing Facilities	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Curtailment of Manufacturing Facilities	Curtailment of Manufacturing Facilities On February 20, 2020, we decided to permanently curtail I-joist production at our Roxboro, North Carolina facility by March 31, 2020. As a result of the curtailment, we recorded $15.0 million of accelerated depreciation during first quarter 2020 to fully depreciate the curtailed I-joist assets. In addition, we recorded $1.7 million of various closure-related costs in "Loss on sale and curtailment of facilities" in our Consolidated Statements of Operations. On November 2, 2018, we decided to permanently curtail LVL production at our Roxboro, North Carolina facility by December 31, 2018. As a result of the curtailment, we recorded $55.0 million of accelerated depreciation during fourth quarter 2018 to fully depreciate the curtailed LVL production assets. In addition, we recorded $2.6 million of construction in progress

Sale of Manufacturing Facilitie

Sale of Manufacturing Facilities	12 Months Ended
	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Sale of Manufacturing Facilities	Sale of Manufacturing Facilities In December 2018, we committed to sell a hardwood plywood facility located in Moncure, North Carolina, and subsequently entered into a definitive sale agreement in January 2019 (the Moncure Sale). This facility generated net sales and operating loss of approximately $5.5 million and $1.4 million, respectively, during the year ended December 31, 2019, and net sales and operating loss of approximately $32.7 million and $7.0 million, respectively, during the year ended December 31, 2018. These results are included in the operating results of our Wood Products segment. On March 1, 2019, we closed on the Moncure Sale and received proceeds of $2.5 million. The disposal group met the criteria to be classified as held for sale in December 2018. Upon classification as held for sale, we discontinued depreciation of the long-lived assets, and performed an assessment of impairment to identify and expense any excess of carrying value over fair value less costs to sell. As a result, we recorded pre-tax impairment and sale-related losses of $24.0 million during the year ended December 31, 2018, recorded in "Loss on sale and curtailment of facilities" in our Consolidated Statements of Operations. On September 10, 2018, we entered into an agreement to sell two lumber mills and a particleboard plant located in Northeast Oregon (the Sale). These facilities generated net sales and operating loss of approximately $74.1 million and $0.2 million, respectively, for the year ended December 31, 2018. These results are included in the operating results of our Wood Products segment. On November 2, 2018, we closed on the Sale and received proceeds of $15.0 million. As a result, we recorded a pre-tax loss of $11.5 million during the year ended December 31, 2018, recorded in "Loss on sale and curtailment of facilities" in our Consolidated Statements of Operations.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions During the year ended December 31, 2019, our wholly owned subsidiary, Boise Cascade Building Materials Distribution, L.L.C., completed the acquisition of a wholesale building material distribution location in Birmingham, Alabama (the Acquisition). The purchase price of the Acquisition was $15.7 million, including a post-closing adjustment of less than $0.1 million based upon a working capital target. During the year ended December 31, 2018, our wholly owned subsidiary, Boise Cascade Building Materials Distribution, L.L.C., completed the acquisition of wholesale building material distribution locations in Nashville, Tennessee, Medford, Oregon, and Cincinnati, Ohio (collectively, the 2018 Acquisitions). The purchase price of the 2018 Acquisitions was $25.5 million.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill represents the excess of the purchase price and related costs over the fair value of the net tangible and intangible assets of businesses acquired. The carrying amount of our goodwill by segment is as follows: Building Wood Products Total (thousands) Balance at December 31, 2020 and 2019 $ 11,792 $ 48,590 $ 60,382 At December 31, 2020 and 2019, intangible assets represented the values assigned to trade names and trademarks and customer relationships. The trade names and trademarks have indefinite lives and are not amortized. The weighted-average useful life for customer relationships from the date of purchase is approximately 10 years. Amortization expense is expected to be approximately $1.2 million per year for the next five years. Intangible assets consisted of the following: December 31, 2020 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (4,776) 7,674 $ 21,350 $ (4,776) $ 16,574 December 31, 2019 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (3,553) 8,897 $ 21,350 $ (3,553) $ 17,797

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Long-term debt consisted of the following: December 31, December 31, (thousands) Asset-based revolving credit facility due 2025 $ — $ — Asset-based credit facility term loan due 2025 50,000 50,000 Term loan due 2026 — 45,000 4.875% senior notes due 2030 400,000 — 5.625% senior notes due 2024 — 350,000 Deferred financing costs (6,208) (4,456) Long-term debt $ 443,792 $ 440,544 At December 31, 2020, the maturities for the aggregate amount of long-term debt outstanding were as follows (in thousands): 2021 $ — 2022 — 2023 — 2024 — 2025 50,000 Thereafter 400,000 Asset-Based Credit Facility On May 15, 2015, Boise Cascade and its principal operating subsidiaries, Boise Cascade Wood Products, L.L.C., and Boise Cascade Building Materials Distribution, L.L.C., as borrowers, and Boise Cascade Wood Products Holdings Corp., as guarantor, entered into an Amended and Restated Credit Agreement, as amended, (Amended Agreement) with Wells Fargo Capital Finance, LLC, as administrative agent, and the banks named therein as lenders. On March 13, 2020, we entered into the sixth amendment to the Amended Agreement to reduce the maximum amount available for revolving loans from $370 million to $350 million (Revolving Credit Facility) and to extend the maturity date of the Credit Agreement from May 1, 2022, to March 13, 2025. The term loan within the Amended Agreement remains at $50.0 million (ABL Term Loan). Interest on borrowings under our Revolving Credit Facility and ABL Term Loan are payable monthly. Borrowings under the Amended Agreement are constrained by a borrowing base formula dependent upon levels of eligible receivables and inventory reduced by outstanding borrowings and letters of credit (Availability). The Amended Agreement is secured by a first-priority security interest in substantially all of our assets, except for property and equipment. The proceeds of borrowings under the agreement are available for working capital and other general corporate purposes. The Amended Agreement contains customary nonfinancial covenants, including a negative pledge covenant and restrictions on new indebtedness, investments, distributions to equity holders, asset sales, and affiliate transactions, the scope of which are dependent on the Availability existing from time to time. The Amended Agreement also contains a requirement that we meet a 1:1 fixed-charge coverage ratio (FCCR), applicable only if Availability falls below 10% of the aggregate revolving lending commitments (or $35 million). Availability exceeded the minimum threshold amounts required for testing of the FCCR at all times since entering into the Amended Agreement, and Availability at December 31, 2020, was $345.2 million. The Amended Agreement permits us to pay dividends only if at the time of payment (i) no default has occurred or is continuing (or would result from such payment) under the Amended Agreement, and (ii) pro forma Excess Availability (as defined in the Amended Agreement) is equal to or exceeds 25% of the aggregate Revolver Commitments (as defined in the Amended Agreement) or (iii) (x) pro forma Excess Availability is equal to or exceeds 15% of the aggregate Revolver Commitment and (y) our fixed-charge coverage ratio is greater than or equal to 1:1 on a pro forma basis. Revolving Credit Facility Interest rates under the Revolving Credit Facility are based, at our election, on either LIBOR or a base rate, as defined in the Amended Agreement, plus a spread over the index elected that ranges from 1.25% to 1.50% for loans based on LIBOR and from 0.25% to 0.50% for loans based on the base rate. The spread is determined on the basis of a pricing grid that results in a higher spread as average quarterly Availability declines. Letters of credit are subject to a fronting fee payable to the issuing bank and a fee payable to the lenders equal to the LIBOR margin rate. In addition, we are required to pay an unused commitment fee at a rate of 0.25% per annum of the average unused portion of the lending commitments. At both December 31, 2020 and 2019, we had no borrowings outstanding under the Revolving Credit Facility and $4.8 million and $4.6 million, respectively, of letters of credit outstanding. These letters of credit and borrowings, if any, reduce Availability under the Revolving Credit Facility by an equivalent amount. ABL Term Loan The ABL Term Loan was provided by institutions within the Farm Credit system. Borrowings under the ABL Term Loan may be repaid from time to time at the discretion of the borrowers without premium or penalty. However, any principal amount of ABL Term Loan repaid may not be subsequently re-borrowed. Interest rates under the ABL Term Loan are based, at our election, on either LIBOR or a base rate, as defined in the Amended Agreement, plus a spread over the index elected that ranges from 1.75% to 2.00% for LIBOR rate loans and from 0.75% to 1.00% for base rate loans, both dependent on the amount of Average Excess Availability (as defined in the Amended Agreement). During the year ended December 31, 2020, the average interest rate on the ABL Term Loan was approximately 2.33%. We have received and expect to continue receiving patronage credits under the ABL Term Loan. Patronage credits are distributions of profits from banks in the Farm Credit system, which are cooperatives that are required to distribute profits to their members. Patronage distributions, which are generally made in cash, are received in the year after they are earned. Patronage credits are recorded as a reduction to interest expense in the year earned. After giving effect to expected patronage distributions, the effective average net interest rate on the ABL Term Loan was approximately 1.3% during the year ended December 31, 2020. Term Loan On March 30, 2016 (Closing Date), Boise Cascade and its principal operating subsidiaries, Boise Cascade Wood Products, L.L.C., and Boise Cascade Building Materials Distribution, L.L.C., as borrowers, and the guarantors party thereto, entered into a term loan agreement, as amended, (Term Loan Agreement) with American AgCredit, PCA, as administrative agent and sole lead arranger, and other banks in the Farm Credit system named therein as lenders. The original Term Loan Agreement was for a $75.0 million secured term loan (Term Loan). In December 2016, we repaid $30 million of the Term Loan. In July 2020, we paid off the remaining balance on the Term Loan of $45.0 million, thus satisfying and discharging our obligations under the Term Loan. Interest rates under the Term Loan Agreement were based, at our election, on either the LIBOR or a base rate, as defined in the Term Loan Agreement, plus a spread over the index. The applicable spread for the Term Loan ranges from 1.875% to 2.125% for LIBOR rate loans, and 0.875% to 1.125% for base rate loans, both dependent on our Interest Coverage Ratio (as defined in the Term Loan Agreement). During the year ended December 31, 2020, the average interest rate on the Term Loan was approximately 2.82%. We have received and expect to receive patronage credits through the period in which the Term Loan was outstanding. After giving effect to expected patronage distributions, the effective average net interest rate on the Term Loan was approximately 1.8%. 2024 Notes On August 29, 2016, Boise Cascade issued $350 million of 5.625% senior notes due September 1, 2024 (2024 Notes), through a private placement that was exempt from the registration requirements of the Securities Act of 1933, as amended (Securities Act). Interest on our 2024 Notes was payable semiannually in arrears on March 1 and September 1. In connection with the issuance of the $400 million of 4.875% senior notes due July 1, 2030 (2030 Notes) described below, we commenced a tender offer to purchase any and all of our $350 million aggregate principal amount of 2024 Notes then outstanding. On July 27, 2020, we accepted for purchase an aggregate principal amount of $212.5 million of the 2024 Notes that were tendered. On September 1, 2020, we redeemed the remaining $137.5 million in aggregate principal amount of the 2024 Notes outstanding and our obligations under the indenture, pursuant to which the 2024 Notes were issued, were satisfied and discharged. In connection with these transactions, we recognized a pre-tax loss on the extinguishment of debt of $14.0 million during the year ended December 31, 2020. The loss includes $10.8 million of debt extinguishment premium payments and $3.2 million for the write-off of unamortized deferred financing costs. 2030 Notes On July 27, 2020, we issued the 2030 Notes through a private placement that was exempt from the registration requirements of the Securities Act. The 2030 Notes mature on July 1, 2030, with interest payable semiannually in arrears on January 1 and July 1, commencing on January 1, 2021. The 2030 Notes are guaranteed by each of our existing and future direct or indirect domestic subsidiaries that is a guarantor under our Amended Agreement. Following the sale of our 2030 Notes, as noted above, we used the net proceeds of the sale to repurchase or redeem any and all of our 2024 Notes, to pay off our Term Loan of $45.0 million, and to pay related financing fees and expenses related to the offering of the 2030 Notes and incurred in connection with the repurchase or redemption of the 2024 Notes. The 2030 Notes are senior unsecured obligations and rank equally with all of the existing and future senior indebtedness of Boise Cascade Company and of the guarantors, senior to all of their existing and future subordinated indebtedness, effectively subordinated to all of their present and future senior secured indebtedness (including all borrowings with respect to our Amended Agreement to the extent of the value of the assets securing such indebtedness), and structurally subordinated to the indebtedness of any subsidiaries that do not guarantee the 2030 Notes. The terms of the indenture governing the 2030 Notes, among other things, limit the ability of Boise Cascade and our restricted subsidiaries to: incur additional debt; declare or pay dividends; redeem stock or make other distributions to stockholders; make investments; create liens on assets; consolidate, merge or transfer substantially all of their assets; enter into transactions with affiliates; and sell or transfer certain assets. The indenture governing the 2030 Notes permits us to pay dividends only if at the time of payment (i) no default has occurred or is continuing (or would result from such payment) under the indenture, and (ii) our consolidated leverage ratio is no greater than 3.5:1, or (iii) the dividend, together with other dividends since the issue date, would not exceed our "builder" basket under the indenture. In addition, the indenture includes certain specific baskets for the payment of dividends. The indenture governing the 2030 Notes provides for customary events of default and remedies. Interest Rate Swaps For information on interest rate swaps, see Interest Rate Risk and Interest Rate Swaps of Note 16, Financial Instrument Risk. Cash Paid for Interest For the years ended December 31, 2020, 2019, and 2018, cash payments for interest were $22.2 million, $24.1 million, and $24.1 million, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lessee, Operating Leases	Leases Adoption of ASC Topic 842, "Leases" On January 1, 2019, we adopted Topic 842 using the modified retrospective transition method and used the effective date as our date of initial application. Consequently, leases for reporting periods beginning after January 1, 2019 are presented under Topic 842, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under Topic 840. Lease Costs The components of lease expense were as follows: Year Ended December 31 2020 2019 (thousands) Operating lease cost $ 13,339 $ 13,541 Finance lease cost Amortization of right-of-use assets 2,210 1,616 Interest on lease liabilities 2,271 1,899 Variable lease cost 2,967 2,645 Short-term lease cost 4,115 4,614 Sublease income (140) (540) Total lease cost $ 24,762 $ 23,775 Other Information Supplemental cash flow information related to leases was as follows: Year Ended December 31 2020 2019 (thousands) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 13,018 $ 13,508 Operating cash flows from finance leases 2,271 1,862 Financing cash flows from finance leases 1,307 783 Right-of-use assets obtained in exchange for lease obligations Operating leases 8,310 4,211 Finance leases 9,969 2,637 Other information related to leases was as follows: December 31, 2020 December 31, 2019 Weighted-average remaining lease term (years) Operating leases 8 8 Finance leases 15 14 Weighted-average discount rate Operating leases (a) 6.4 % 6.5 % Finance leases 7.7 % 8.5 % ___________________________________ (a) Upon adoption of the new lease standard, discount rates used for existing leases were established at January 1, 2019. As of December 31, 2020, our minimum lease payment requirements for noncancelable operating and finance leases are as follows: Operating Leases Finance Leases (thousands) 2021 $ 13,593 $ 3,924 2022 13,024 3,930 2023 12,073 3,970 2024 11,189 3,967 2025 9,448 3,607 Thereafter 25,545 37,801 Total future minimum lease payments 84,872 57,199 Less: interest (18,945) (24,035) Total lease obligations 65,927 33,164 Less: current obligations (9,926) (1,557) Long-term lease obligations $ 56,001 $ 31,607 As of December 31, 2020, the minimum lease payment amount for leases signed but not yet commenced was $7.3 million. Disclosures Related to Periods Prior to Adoption of ASC Topic 842, "Leases"
Lessee, Finance Leases	Leases Adoption of ASC Topic 842, "Leases" On January 1, 2019, we adopted Topic 842 using the modified retrospective transition method and used the effective date as our date of initial application. Consequently, leases for reporting periods beginning after January 1, 2019 are presented under Topic 842, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under Topic 840. Lease Costs The components of lease expense were as follows: Year Ended December 31 2020 2019 (thousands) Operating lease cost $ 13,339 $ 13,541 Finance lease cost Amortization of right-of-use assets 2,210 1,616 Interest on lease liabilities 2,271 1,899 Variable lease cost 2,967 2,645 Short-term lease cost 4,115 4,614 Sublease income (140) (540) Total lease cost $ 24,762 $ 23,775 Other Information Supplemental cash flow information related to leases was as follows: Year Ended December 31 2020 2019 (thousands) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 13,018 $ 13,508 Operating cash flows from finance leases 2,271 1,862 Financing cash flows from finance leases 1,307 783 Right-of-use assets obtained in exchange for lease obligations Operating leases 8,310 4,211 Finance leases 9,969 2,637 Other information related to leases was as follows: December 31, 2020 December 31, 2019 Weighted-average remaining lease term (years) Operating leases 8 8 Finance leases 15 14 Weighted-average discount rate Operating leases (a) 6.4 % 6.5 % Finance leases 7.7 % 8.5 % ___________________________________ (a) Upon adoption of the new lease standard, discount rates used for existing leases were established at January 1, 2019. As of December 31, 2020, our minimum lease payment requirements for noncancelable operating and finance leases are as follows: Operating Leases Finance Leases (thousands) 2021 $ 13,593 $ 3,924 2022 13,024 3,930 2023 12,073 3,970 2024 11,189 3,967 2025 9,448 3,607 Thereafter 25,545 37,801 Total future minimum lease payments 84,872 57,199 Less: interest (18,945) (24,035) Total lease obligations 65,927 33,164 Less: current obligations (9,926) (1,557) Long-term lease obligations $ 56,001 $ 31,607 As of December 31, 2020, the minimum lease payment amount for leases signed but not yet commenced was $7.3 million. Disclosures Related to Periods Prior to Adoption of ASC Topic 842, "Leases"

Retirement and Benefit Plans

Retirement and Benefit Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Retirement and Benefit Plans	Retirement and Benefit Plans Our retirement plans consist of noncontributory defined benefit pension plans, contributory defined contribution savings plans, a deferred compensation plan, and a multiemployer health and welfare plan. Defined Benefit Plans Some of our employees are covered by noncontributory defined benefit pension plans, including a qualified defined benefit pension plan (Pension Plan) which was eliminated in December 2020 (Plan Termination). Benefits under the Pension Plan have been frozen for salaried employees since 2009 and substantially all eligible hourly employees since 2012. The following summarizes recent activity of each individual plan: • In conjunction with the Plan Termination, we purchased a buy-in group annuity contract (Buy-In) from The Prudential Insurance Company of America (Prudential), which was funded with plan assets on August 6, 2020. In addition, we froze accrual of all remaining benefits of hourly employees on our Pension Plan effective August 31, 2020. In anticipation of the Plan Termination, the Buy-In funded lump-sum payments made to eligible plan participants at their election, on or about December 2, 2020, after which, neither the Pension Plan nor Prudential has any further obligations to those participants. After completion of the lump-sum program, we exercised our option to convert the Buy-In to a buy-out group annuity contract (Buy-Out) for no additional premium. When the Buy-Out became effective on December 31, 2020, we irrevocably transferred to Prudential the future benefit obligations and annuity administration for all remaining plan participants (or their beneficiaries) in the Pension Plan. These transactions fully eliminated the liabilities of our Pension Plan, resulting in a non-cash settlement charge of $6.2 million in fourth quarter 2020. • On September 30, 2019, we transferred $19.8 million of our Pension Plan assets to Prudential for the purchase of a group annuity contract. Under the arrangement, Prudential assumed ongoing responsibility for administration and benefit payments for approximately 10% of our U.S. qualified pension plan projected benefit obligations at the time of the transaction. As a result of the transaction, we recognized a non-cash settlement charge of $1.3 million in third quarter 2019. • On April 25, 2018, and August 10, 2018, we transferred $151.8 million and $124.8 million, respectively, of our Pension Plan assets to Prudential for the purchase of group annuity contracts. Under the arrangements, Prudential assumed ongoing responsibility for administration and benefit payments for over 60% of our U.S. qualified pension plan projected benefit obligations. As a result of the transfers of pension plan assets, we recorded settlement expense in second and third quarters 2018 of $12.0 million and $11.3 million, respectively. See "Assumptions" below for the impact on our discount rate and expected return on plan asset assumptions. We also have nonqualified salaried pension plans, which were frozen so that no future benefits have accrued since December 31, 2009. Defined Contribution Plans We sponsor contributory defined contribution savings plans for most of our salaried and hourly employees, and we generally provide company contributions to the savings plans. Since March 1, 2010, we have contributed 4% of each salaried participant's eligible compensation to the plan as a nondiscretionary company contribution. In addition, beginning in 2012, for the years that a performance target is met, we contribute an additional amount of the employee's eligible compensation, depending on company performance and the employee's years of service. During the years ended December 31, 2020, 2019, and 2018, company performance resulted in additional contributions in the range of 2% to 4%, 1.6% to 3.1%, and 2% to 4%, respectively, of eligible compensation. The company contributions for union and nonunion hourly employees vary by location. Company contributions paid, or to be paid, to our defined contribution savings plans for the years ended December 31, 2020, 2019, and 2018, were $23.4 million, $19.8 million, and $22.2 million, respectively. Defined Contributory Trust We participated in a multiemployer defined contributory trust plan for certain union hourly employees since 2013. As of December 31, 2020, 2019, and 2018 approximately 735, 1,215, and 1,221, respectively, of our employees participated in this plan. For certain of these employees, per the terms of the representative collective bargaining agreements, we were required to contribute $0.90, $0.90, and $0.85, respectively, per hour per active employee during 2020, 2019, and 2018. For certain other of these employees, we were required to contribute 4.5% of the employee's earnings during 2020, 2019, and 2018. Company contributions to the multiemployer defined contributory trust plan were $2.4 million, $2.6 million, and $2.8 million, respectively, for each of the years ended December 31, 2020, 2019, and 2018. Effective fourth quarter 2020, through collective bargaining negotiations, some of our employees no longer participate in this plan. In addition, for the remaining plan participants, we expect to contribute 4.5% of the employees earnings. After required contributions, we have no further obligation to the plan. The plan and its assets are managed by a joint board of trustees. Deferred Compensation Plan We sponsor a deferred compensation plan. Under the plan, participating employees and directors irrevocably elect each year to defer receipt of a portion of their compensation. A participant's account is credited with imputed interest at a rate equal to 130% of Moody's Composite Average of Yields on Corporate Bonds. Participants may receive payment of their deferred compensation plan balance in a lump sum or in monthly installments over a specified period of years following the termination of their employment with the company. In addition, subject to plan revisions that became effective January 1, 2019, participants may also receive distributions of their deferred compensation accounts while still employed by the company. The deferred compensation plan is unfunded; therefore, benefits are paid from our general assets. For the years ended December 31, 2020, 2019, and 2018, we recognized $1.0 million, $1.1 million, and $1.0 million, respectively, of interest expense related to the plan. At December 31, 2020 and 2019, we had liabilities related to the plan of $5.9 million and $2.1 million, respectively, recorded in "Accrued liabilities, Compensation and benefits" and $19.8 million and $21.6 million, respectively, recorded in "Other, Compensation and benefits" on our Consolidated Balance Sheets. Multiemployer Health and Welfare Plan We have participated in a multiemployer health and welfare plan that covered medical, dental, and life insurance benefits for certain active employees as well as benefits for retired employees. Effective November 30, 2020, through collective bargaining negotiations, our employees no longer participate in this plan. As of December 31, 2019 and 2018, approximately 475 and 604, respectively, of our employees participated in this plan. Per the terms of the representative collective bargaining agreements, we were required to contribute $6.10 per hour per active employee from January 1, 2018, to May 31, 2018. From June 1, 2018, to May 31, 2019, we were required to contribute $6.40 per hour per active employee. From June 1, 2019, to May 31, 2020, we were required to contribute $6.70 per hour per active employee. From June 1, 2020, to November 30, 2020, we were required to contribute $7.00 per hour per active employee. During the years ended December 31, 2020, 2019, and 2018 company contributions to the multiemployer health and welfare plan were $5.8 million, $6.7 million, and $7.7 million, respectively. After required contributions, we have no further obligation to the plan. The trustees of the plan determine the allocation of benefits between active and retired employees. Defined Benefit Obligations and Funded Status The following table, which includes only company-sponsored defined benefit plans, reconciles the beginning and ending balances of our projected benefit obligation and fair value of plan assets. We recognize the underfunded status of our defined benefit pension plans on our Consolidated Balance Sheets. We recognize changes in funded status in the year changes occur through other comprehensive income (loss). December 31 2020 2019 (thousands) Change in benefit obligation Benefit obligation at beginning of year $ 192,061 $ 176,852 Service cost 668 647 Interest cost 5,893 7,210 Actuarial loss 18,605 29,065 Group annuity transactions (a) (76,650) (19,848) Benefits paid (b) (135,690) (1,865) Benefit obligation at end of year 4,887 192,061 Change in plan assets Fair value of plan assets at beginning of year 168,651 154,801 Actual return on plan assets 30,930 29,769 Employer contributions 12,759 5,238 Group annuity transactions (a) (76,650) (19,292) Benefits paid (b) (135,690) (1,865) Fair value of plan assets at end of year — 168,651 Underfunded status $ (4,887) $ (23,410) Amounts recognized on our Consolidated Balance Sheets Current liabilities $ (367) $ (878) Noncurrent liabilities (4,520) (22,532) Net liability $ (4,887) $ (23,410) Amounts recognized in accumulated other comprehensive loss Net actuarial loss $ 1,443 $ 15,332 Prior service cost — — Net loss recognized $ 1,443 $ 15,332 ______________________________________ (a) See Defined Benefits Plans above for description of group annuity transactions. (b) See Defined Benefits Plans above for description of lump-sum payments. The accumulated benefit obligation for all defined benefit pension plans was $4.9 million and $192.1 million at December 31, 2020 and 2019, respectively. After the Plan Termination, the remaining accumulated benefit obligations are from our unfunded nonqualified defined benefit pension plans. Net Periodic Benefit Cost and Other Comprehensive (Income) Loss The components of net periodic benefit cost and other amounts recognized in other comprehensive (income) loss are as follows: Year Ended December 31 2020 2019 2018 (thousands) Net periodic benefit cost Service cost $ 668 $ 647 $ 794 Interest cost 5,893 7,210 11,344 Expected return on plan assets (5,493) (5,903) (11,097) Amortization of actuarial (gain) loss 807 (175) 1,497 Plan settlement expense (a) 6,250 1,342 23,255 Net periodic benefit cost 8,125 3,121 25,793 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Net actuarial (gain) loss (6,832) 4,642 (14,178) Amortization of actuarial gain (loss) (807) 175 (1,497) Effect of settlements (6,250) (1,342) (23,255) Total recognized in other comprehensive (income) loss (13,889) 3,475 (38,930) Total recognized in net periodic cost and other comprehensive (income) loss $ (5,764) $ 6,596 $ (13,137) ______________________________________ (a) Plan settlement expense during the years ended December 31, 2020, 2019, and 2018 includes $6.3 million, $1.3 million and $23.3 million, respectively, of settlement charges related to the transfers of pension plan assets to Prudential for the purchase of group annuity contracts, as well as lump-sum payments in 2020. Assumptions The assumptions used in accounting for our plans are estimates of factors that will determine, among other things, the amount and timing of future contributions. The following table presents the assumptions used in the measurement of our benefit obligations: December 31 2020 2019 Weighted average assumptions Discount rate 2.00 % 3.10 % Rate of compensation increases (a) — % — % The following table presents the assumptions used in the measurement of net periodic benefit cost: December 31 2020 2019 2018 (b) Weighted average assumptions Discount rate 3.10 % 4.15 % 3.95 % / 4.05 % / 3.40 % Expected long-term rate of return on plan assets 3.50 % 3.85 % 3.85 % / 4.50 % / 4.75 % Rate of compensation increases (a) — % — % — % _______________________________________ (a) Pension benefits for all salaried employees are frozen, resulting in an assumption for the rate of compensation increase of zero. (b) Prior to the remeasurements of our qualified defined benefit pension plan on April 25, 2018, and August 10, 2018, the discount rates were 3.40% and 4.05%, respectively, and the expected rates of return on plan assets were 4.75% and 4.50%, respectively. The discount rate and expected rate of return on plan assets after the August 10, 2018 remeasurement were 3.95% and 3.85%, respectively. Discount Rate Assumption . The discount rate reflects the current rate at which the pension obligations could be settled at each measurement date of the plan. In all years presented, the discount rates were determined by matching the expected plan benefit payments against a spot rate yield curve constructed to replicate the yields of Aa-graded corporate bonds. Asset Return Assumption . Prior to the Plan Termination, we based our expected long-term rate of return on plan assets on a weighted average of our expected returns for the major asset classes in which we invest. The weights we assigned each asset class were based on our investment strategy. Expected returns for the asset classes were based on long-term historical returns, inflation expectations, forecasted gross domestic product, earnings growth, and other economic factors. We developed our return assumption based on a review of the fund manager's estimates of future market expectations by broad asset class and expected long-term rates of return from external investment managers. Retirement and Mortality Rates . These rates are developed to reflect actual and projected plan experience. In 2020, we used the Pri-2012 mortality tables projected forward using MP-2020 on a generational basis. In 2019, we used the Pri-2012 mortality tables projected forward using MP-2019 on a generational basis. Fair Value Measurements of Plan Assets The following table sets forth by level, within the fair value hierarchy, the pension plan assets, by major asset category, at fair value at December 31, 2019: December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (thousands) Fixed-income securities (b) $ — $ 152,530 $ — $ 152,530 Multi-asset class fund (c) — 16,361 — 16,361 Total investments at fair value $ — $ 168,891 $ — 168,891 Receivables and accrued expenses, net (240) Fair value of plan assets $ 168,651 _______________________________________ (a) Securities represent common collective trusts managed and valued by Russell Trust Company, the administrator of the funds. While the underlying assets are actively traded on an exchange, the funds are not. The investments in equity and fixed-income securities are considered to have a readily determinable fair value because the fair value per share (unit) is determined and published and is the basis for current transactions. We had the ability to redeem these securities with a 1 day notice. (b) Invested in the Russell Long Duration Fixed Income Fund, which is designed to provide current income and capital appreciation through diversified strategies including sector rotation, modest interest rate timing, security selection, and tactical use of high-yield, emerging market bonds and other non-index securities. In addition, our investments in this category included the Russell 14 Year LDI Fixed Income Fund. We also were invested in the Russell 8 Year LDI Fixed Income Fund. These LDI funds invest primarily in investment grade bonds that closely match those found in discount rate curves used to value U.S. pension liabilities and seeks to provide additional incremental return through modest interest rate timing, security selection, and tactical use of non-credit sectors. In addition, our investments in this category included Russell STRIPS Fixed Income Funds with duration profiles of 10, 15, and 28 years. These funds invest in a subset of the STRIPS universe with a similar duration profile as their respective Bloomberg Barclays U.S. STRIPS Index. (c) Invested in the Russell Multi-Asset Core Plus Fund, which is designed to provide long-term growth by providing a diversified portfolio of investments that has an overall strategic allocation of 75% global equity, 15% marketable real assets, and 10% global fixed income. Cash Flows Since 2012, we contributed a total of four company-owned real property locations from our Building Materials Distribution segment to our Pension Plan, which we then leased from the Pension Plan. These contributions constituted related party transactions. We determined that these contributed properties did not meet the accounting definition of a plan asset within the scope of Accounting Standards Codification 715, Compensation - Retirement Benefits , and, therefore, were not included in plan assets and had no impact on the net pension liability. However, the lease payments and payments for the repurchase of the contributed properties are recorded as pension contributions. During the years ended December 31, 2020, 2019, and 2018, we repurchased two, one, and one, respectively, of the real property locations we previously had contributed to our Pension Plan for approximately $11.4 million (the 2020 Repurchases), $3.6 million (the 2019 Repurchase) and $4.0 million (the 2018 Repurchase), respectively, which were recorded as pension contributions. Our practice is to fund the pension plans in amounts sufficient to meet the minimum requirements of U.S. federal laws and regulations. For the years ended December 31, 2020, 2019, and 2018, we made cash contributions to our pension plans totaling $12.8 million, $5.2 million, and $26.1 million, respectively. During 2020, cash contributions include $11.4 million for the 2020 Repurchases and $0.6 million of lease payments. During 2019, cash contributions include $3.6 million for the 2019 Repurchase and $1.1 million of lease payments. During 2018, cash contributions include a $20.0 million discretionary contribution, $4.0 million for the 2018 Repurchase, and $1.5 million of lease payments. After the Plan Termination, we will have no federally required contributions to the Pension Plan. For 2021, we expect to make cash contributions of approximately $0.4 million to our nonqualified pension plans, reflecting benefit payments to plan participants. Nonqualified pension benefit payments are paid by the company. The following benefit payments are expected to be paid to nonqualified plan participants (in thousands): 2021 $ 367 2022 380 2023 382 2024 368 2025 314 Years 2026-2030 1,373

Long-Term Incentive Compensatio

Long-Term Incentive Compensation Plans	12 Months Ended
	Dec. 31, 2020
Compensation Related Costs [Abstract]
Long-Term Incentive Compensation Plans [Text Block]	Long-Term Incentive Compensation Plans Stock-Based Compensation In April 2016, we adopted the 2016 Boise Cascade Omnibus Incentive Plan (2016 Incentive Plan), which superseded the 2013 Incentive Compensation Plan (2013 Incentive Plan). After the effective date of the 2016 Incentive Plan, no awards were granted under the 2013 Incentive Plan. The 2016 Incentive Plan provides for grants of stock options, stock appreciation rights, restricted stock, other stock-based awards, cash-based compensation, and performance awards. Directors, officers, and other employees, as well as consultants and advisors, are eligible for grants under the 2016 Incentive Plan. These awards are at the discretion of the Compensation Committee of our board of directors, and they vest and expire in accordance with terms established at the time of grant. All awards under the 2016 Incentive Plan, other than stock options or stock appreciation rights, are eligible to participate in dividend or dividend equivalent payments, if any, which we accrue to be paid when the awards vest. Shares issued pursuant to awards under the incentive plans are from our authorized but unissued shares. The maximum number of shares approved for grant under the 2016 Incentive Plan is 3.7 million shares. In 2020, 2019, and 2018, we granted two types of stock-based awards under the 2016 Incentive Plan: performance stock units (PSUs) and restricted stock units (RSUs). As of December 31, 2020, 2.5 million shares remained available for future issuance under the 2016 Incentive Plan. PSU and RSU Awards In 2020, we granted 94,850 PSUs to our officers and other employees, subject to performance and service conditions, at a weighted average grant date fair value of $36.45. For the officers, the number of shares actually awarded will range from 0% to 200% of the target amount, dependent upon Boise Cascade's 2020 return on invested capital (ROIC), as approved by our Compensation Committee in accordance with the related grant agreement. For the other employees, the number of shares actually awarded will range from 0% to 200% of the target amount, depending upon Boise Cascade's 2020 EBITDA, defined as income before interest (interest expense and interest income), income taxes, and depreciation and amortization, determined in accordance with the related grant agreement. Because the ROIC and EBITDA components contain a performance condition, we record compensation expense over the requisite service period based on the most probable number of shares expected to vest. In 2019 and 2018, we granted 110,923 and 78,976 PSUs, at a weighted average grant date fair value of $29.48 and $43.05, respectively, to our officers and other employees, subject to performance and service conditions. During the 2019 performance period, officers and other employees earned 93% and 96%, respectively, of the target based on Boise Cascade’s 2019 ROIC and EBITDA, determined by our Compensation Committee in accordance with the related grant agreements. During the 2018 performance period, officers and other employees earned 100% and 110%, respectively, of the target based on Boise Cascade’s 2018 ROIC and EBITDA, determined by our Compensation Committee in accordance with the related grant agreements. The PSUs granted to officers generally vest in a single installment three years from the grant date, while the PSUs granted to other employees vest in three equal tranches each year after the grant date. In 2020, 2019, and 2018, we granted an aggregate of 125,716, 167,861, and 99,087 RSUs, at a weighted average grant date fair value of $36.45, $29.13, and $43.08, respectively, to our officers, other employees, and nonemployee directors with only service conditions. The RSUs granted to officers and other employees vest in three equal tranches each year after the grant date. The RSUs granted to nonemployee directors vest over a one year period. We based the fair value of PSU and RSU awards on the closing market price of our common stock on the grant date. During the years ended December 31, 2020, 2019, and 2018, the total fair value of PSUs and RSUs vested was $11.1 million, $11.4 million, and $15.4 million, respectively. The following summarizes the activity of our PSUs and RSUs awarded under our incentive plan for the year ended December 31, 2020: PSUs RSUs Number of shares Weighted Average Grant-Date Fair Value Number of shares Weighted Average Grant-Date Fair Value Outstanding, December 31, 2019 295,347 $ 31.09 257,564 $ 31.14 Granted 94,850 36.45 125,716 36.45 Performance condition adjustment (a) (6,989) 29.48 — — Vested (162,622) 28.93 (143,807) 30.88 Forfeited (24,246) 32.57 (26,707) 32.82 Outstanding, December 31, 2020 196,340 $ 35.34 212,766 $ 34.24 __________________ (a) Represents total PSUs forfeited during the year ended December 31, 2020, related to the 2019 performance condition adjustment described above. Compensation Expense We record compensation expense over the awards' vesting period and account for share-based award forfeitures as they occur, rather than making estimates of future forfeitures. Any shares not vested are forfeited. We recognize stock awards with only service conditions on a straight-line basis over the requisite service period. Most of our share-based compensation expense was recorded in "General and administrative expenses" in our Consolidated Statements of Operations. Total stock-based compensation recognized from PSUs and RSUs, net of forfeitures, was as follows: Year Ended December 31 2020 2019 2018 (thousands) PSUs $ 3,795 $ 3,340 $ 4,005 RSUs 4,025 4,633 4,826 Total $ 7,820 $ 7,973 $ 8,831 For the years ended December 31, 2020, 2019, and 2018, the related tax benefit was $2.0 million, $2.0 million, and $2.2 million, respectively. As of December 31, 2020, total unrecognized compensation expense related to nonvested share-based compensation arrangements was $9.2 million. This expense is expected to be recognized over a weighted-average period of 1.9 years. Long-Term Incentive Cash Plan In 2020, 2019, and 2018, certain non-executive employees participated in a long-term incentive plan that pays awards in cash (LTI Cash Plan). The LTI Cash Plan provides an award notice to participants granting them the opportunity to earn a cash award, half of which is subject to service conditions only, with the other half subject to performance and service conditions. For the performance based cash award, the amount of cash actually awarded will range from 0% to 200% of the target amount, depending upon Boise Cascade's EBITDA, determined in accordance with the related grant agreement. Under the LTI Cash Plan, the award is paid in three equal installments each year after the grant date, with continued employment as a precondition for receipt of each award installment. We recognize compensation for cash awards with only service conditions on a straight-line basis over the requisite service period. Cash awards subject to performance conditions are also recognized on a straight-line basis over the requisite service period, based on the most probable amount of cash to be paid subject to achievement of the performance condition. In 2020, 2019, and 2018, we recognized $3.9 million, $2.2 million, and $1.4 million, respectively, of LTI Cash Plan expense, primarily recorded in "General and administrative expenses" in our Consolidated Statements of Operations. During the 2019 and 2018 performance periods, cash awards earned 96% and 110%, respectively, of the target based on Boise Cascade’s 2019 and 2018 EBITDA, respectively, determined by our Compensation Committee in accordance with the related grant agreements.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' Equity Our certificate of incorporation has authorized 300,000,000 shares of common stock and 50,000,000 shares of preferred stock. No preferred stock was issued or outstanding as of December 31, 2020 and 2019. We had 44,568,299 and 44,352,778 shares of common stock issued and 39,201,226 and 38,985,705 shares of common stock outstanding as of December 31, 2020 and 2019, respectively. Each share of common stock entitles the holder to one vote on matters to be voted on by the stockholders of Boise Cascade. Dividends On November 14, 2017, we announced that our board of directors approved a dividend policy to pay quarterly cash dividends to holders of our common stock. Our board of directors declared and paid the following dividends during each of the respective quarters for the years ended December 31, 2020, 2019, and 2018: Dividends Per Share Amount Paid 2020 (in thousands) First Quarter (a) $ 0.10 $ 4,645 Second Quarter 0.10 3,917 Third Quarter (b) 1.70 3,991 Fourth Quarter (b) 0.10 66,642 Total $ 2.00 $ 79,195 2019 First Quarter (a) $ 0.09 $ 4,053 Second Quarter 0.09 3,509 Third Quarter 0.09 3,508 Fourth Quarter (c) 1.10 42,884 Total $ 1.37 $ 53,954 2018 First Quarter (a) $ 0.07 $ 2,758 Second Quarter 0.07 2,723 Third Quarter (c) 1.07 41,632 Fourth Quarter 0.09 3,502 Total $ 1.30 $ 50,615 __________________ (a) Includes payments of dividend equivalents on RSUs and PSUs which vested in first quarter of each year. (b) During third quarter 2020, our board of directors declared a supplemental dividend of $1.60 per share on our common stock, which was paid in fourth quarter 2020. (c) During each fourth quarter 2019 and third quarter 2018, our board of directors declared and paid a supplemental dividend of $1.00 per share of our common stock. On February 5, 2021, our board of directors declared a dividend of $0.10 per share of our common stock, payable on March 15, 2021, to stockholders of record on February 22, 2021. For a description of the restrictions in our asset-based credit facility and the indenture governing our senior notes on our ability to pay dividends, see Note 10, Debt. Future quarterly dividend declarations, including amount per share, record date and payment date, will be made at the discretion of our board of directors and will depend upon, among other things, legal capital requirements and surplus, our future operations and earnings, general financial condition, contractual obligations, restrictions imposed by our asset-based credit facility and the indenture governing our senior notes, applicable laws, and other factors that our board of directors may deem relevant. Stock Repurchase On February 25, 2015, our board of directors authorized a two million share repurchase program (Program) pursuant to which we may, from time to time, purchase shares of our common stock through various means including, without limitation, open market transactions, privately negotiated transactions, or accelerated share repurchase transactions. We are not obligated to purchase any shares and there is no set date that the Program will expire. The board may increase or decrease the number of shares under the Program or terminate the Program in its discretion at any time. During 2020 and 2019, we did not purchase any shares under the Program. During 2018, we repurchased 200,000 shares under the program at a cost of $4.9 million, or an average of $24.65 per share. The shares were purchased with cash on hand and are recorded as "Treasury stock" on our Consolidated Balance Sheet. As of December 31, 2020, there were 496,989 shares of common stock that may yet be purchased under the Program. Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss are as follows: Changes in Accumulated Other Comprehensive Loss Year Ended December 31 2020 2019 2018 (thousands) Beginning Balance, net of taxes $ (50,248) $ (47,652) $ (76,702) Net actuarial gain (loss), before taxes 6,832 (4,642) 14,178 Amortization of actuarial (gain) loss, before taxes (a) 807 (175) 1,497 Effect of settlements, before taxes (a) 6,250 1,342 23,255 Income taxes (b) 35,281 879 (9,880) Ending Balance, net of taxes $ (1,078) $ (50,248) $ (47,652) ___________________________________ (a) Represents amounts reclassified from accumulated other comprehensive loss. These amounts are included in the computation of net periodic pension cost. For additional information, see Note 12, Retirement and Benefit Plans. (b) For the year ended December 31, 2020, income taxes include $38.8 million related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.

Transactions With Related Party

Transactions With Related Party	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Transactions With Related Parties	Transactions With Related Party Louisiana Timber Procurement Company, L.L.C. (LTP) is an unconsolidated variable-interest entity that is 50% owned by us and 50% owned by Packaging Corporation of America (PCA). LTP procures sawtimber, pulpwood, residual chips, and other residual wood fiber to meet the wood and fiber requirements of us and PCA in Louisiana. We are not the primary beneficiary of LTP as we do not have power to direct the activities that most significantly affect the economic performance of LTP. Accordingly, we do not consolidate LTP's results in our financial statements. Sales Related-party sales to LTP from our Wood Products segment in our Consolidated Statements of Operations were $12.6 million, $16.5 million, and $16.7 million, respectively, during the years ended December 31, 2020, 2019, and 2018. These sales are recorded in "Sales" in our Consolidated Statements of Operations. Costs and Expenses Related-party wood fiber purchases from LTP were $70.6 million, $81.7 million, and $83.1 million, respectively, during the years ended December 31, 2020, 2019, and 2018. These costs are recorded in "Materials, labor, and other operating expenses (excluding depreciation)" in our Consolidated Statements of Operations.

Financial Instrument Risk

Financial Instrument Risk	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instrument Risk	Financial Instrument Risk In the normal course of business, we are exposed to financial risks such as changes in commodity prices, interest rates, and foreign currency exchange rates. In 2020, 2019, and 2018, we did not use derivative instruments to manage these risks, except for interest rate swaps as discussed below. Commodity Price Risk Many of the products we manufacture or purchase and resell and some of our key production inputs are commodities whose price is determined by the market's supply and demand for such products. Price fluctuations in our selling prices and key costs have a significant effect on our financial performance. The markets for most of these commodities are cyclical and are primarily affected by various economic and industry factors, including the strength of the U.S. housing market, net import and export activity, changes in or disruptions to industry production capacity, changes in inventory levels, and other factors beyond our control. Interest Rate Risk We are exposed to interest rate risk arising from fluctuations in variable-rate LIBOR on our term loan and when we have loan amounts outstanding on our Revolving Credit Facility. At December 31, 2020, we had $50.0 million of variable-rate debt outstanding based on one-month LIBOR after the pay-off of our $45.0 million term loan in July 2020, described in Note 10, Debt. During the year ended December 31, 2020, we liquidated our interest rate swap agreements with notional principal amounts of $45.0 million in conjunction with the pay-off of the $45.0 million term loan. Our objective is to limit the variability of interest payments on our debt. To meet this objective, we enter into receive-variable, pay-fixed interest rate swaps to change the variable-rate cash flow exposure to fixed-rate cash flows. In accordance with our risk management strategy, we actively monitor our interest rate exposure and use derivative instruments from time to time to manage the related risk. We do not speculate using derivative instruments. At December 31, 2020, we had two interest rate swap agreements. Under the interest rate swaps, we receive one-month LIBOR-based variable interest rate payments and make fixed interest rate payments, thereby fixing the interest rate on $50.0 million of variable rate debt exposure. Payments on one interest rate swap, entered into in 2016, with a notional principal amount of $50.0 million is due on a monthly basis at an annual fixed rate of 1.007% and expires in February 2022 (Initial Swap). During second quarter 2020, we entered into another forward interest rate swap agreement which commences on the expiration date of the Initial Swap. Payments on this interest rate swap with a notional principal amount of $50.0 million will be due on a monthly basis at an annual fixed rate of 0.39% and expires in June 2025. The interest rate swap agreements were not designated as cash flow hedges, and as a result, all changes in the fair value are recognized in "Change in fair value of interest rate swaps" in our Consolidated Statements of Operations rather than through other comprehensive income. At December 31, 2020, we recorded a long-term liability of $0.6 million in "Other long-term liabilities" on our Consolidated Balance Sheets, representing the fair value of the interest rate swap agreements. At December 31, 2019, we recorded a long-term asset of $0.8 million in "Other assets" on our Consolidated Balance Sheets, representing the fair value of the interest rate swap agreements. The swaps were valued based on observable inputs for similar assets and liabilities and other observable inputs for interest rates and yield curves (Level 2 inputs). Foreign Currency Risk

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information We operate our business using two reportable segments: Wood Products and Building Materials Distribution. These segments represent distinct businesses that are managed separately because of differing products and services. Each of these businesses requires distinct operating and marketing strategies. Management reviews the performance of the company based on these segments. For a description of the products sold by our segments, see Note 3, Revenues. Unallocated corporate costs include corporate support staff services, related assets and liabilities, and pension plan activity. Support services include, but are not limited to, information technology, human resources, finance, accounting, and legal functions. Specified expenses are allocated to the segments. For many of these allocated expenses, the related assets and liabilities remain in corporate. The segments follow the accounting principles described in Note 2, Summary of Significant Accounting Policies. For the year ended December 31, 2020, one customer accounted for 11% of total sales, when combining sales from Wood Products and BMD to that customer. For the years ended December 31, 2019 and 2018, no customers accounted for 10% or more of total sales. Sales to foreign unaffiliated customers were approximately $71 million, $76 million, and $96 million, respectively, for the years ended December 31, 2020, 2019, and 2018. At December 31, 2020, 2019, and 2018, and for the years then ended, long-lived assets located in foreign countries and net sales originating in foreign countries were not material. Wood Products and Building Materials Distribution segment sales to external customers, including related parties, by product line are as follows: Year Ended December 31 2020 2019 2018 (millions) Wood Products (a) LVL $ 18.4 $ 39.5 $ 42.2 I-joists 7.3 22.1 29.3 Other engineered wood products 23.9 26.8 25.3 Plywood and veneer 332.7 255.1 336.2 Lumber (b) 54.7 52.5 86.0 Byproducts 68.6 75.1 87.3 Particleboard (b) — — 37.5 Other 17.1 34.7 63.9 522.8 505.7 707.7 Building Materials Distribution Commodity 2,309.9 1,725.4 2,070.1 General line 1,762.3 1,580.7 1,421.5 Engineered wood products 879.9 831.6 796.0 4,952.0 4,137.7 4,287.6 $ 5,474.8 $ 4,643.4 $ 4,995.3 ___________________________________ (a) Amounts represent sales to external customers. Sales are calculated after intersegment sales eliminations to our Building Materials Distribution segment, as well as the cost of EWP rebates and sales allowances provided at various stages of the supply chain (including distributors, retail lumberyards, and homebuilders). For the years ended December 31, 2020, 2019, and 2018, approximately 80%, 77%, and 74%, respectively, of Wood Products' EWP sales volumes were to our Building Materials Distribution segment. (b) In fourth quarter 2018, we sold two lumber mills and our particleboard plant located in Northeast Oregon. For additional information, see Note 7, Sale of Manufacturing Facilities. An analysis of our operations by segment is as follows: Year Ended December 31 2020 2019 2018 (thousands) Net sales by segment Wood Products $ 1,323,901 $ 1,275,167 $ 1,533,270 Building Materials Distribution 4,952,018 4,137,719 4,287,702 Intersegment eliminations (a) (801,081) (769,482) (825,682) Total net sales $ 5,474,838 $ 4,643,404 $ 4,995,290 Segment operating income (loss) Wood Products (b) $ 127,720 $ 54,197 $ (10,022) Building Materials Distribution 247,494 116,236 112,510 Total segment operating income 375,214 170,433 102,488 Unallocated corporate costs (40,185) (33,974) (30,450) Income from operations $ 335,029 $ 136,459 $ 72,038 Depreciation and amortization Wood Products (c) $ 71,141 $ 57,671 $ 126,989 Building Materials Distribution 22,460 20,769 18,280 Corporate 1,568 1,701 1,568 Total depreciation and amortization $ 95,169 $ 80,141 $ 146,837 Capital expenditures Wood Products $ 38,230 $ 53,460 $ 53,392 Building Materials Distribution (d) 39,976 40,722 51,306 Corporate 1,223 4,214 771 Total capital expenditures $ 79,429 $ 98,396 $ 105,469 __________________ (a) Primarily represents intersegment sales from our Wood Products segment to our Building Materials Distribution segment. During 2020, 2019, and 2018, approximately 61%, 60%, and 54%, respectively, of Wood Products' overall sales were to our Building Materials Distribution segment. (b) Wood Products segment operating income for the year ended December 31, 2020, includes $15.0 million of accelerated depreciation and $1.7 million of other closure-related costs due to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility. In addition, Wood Products segment operating loss for the year ended December 31, 2018, includes pre-tax facility impairment and sales related losses of $35.5 million, as well as $57.8 million of accelerated depreciation and other curtailment costs related to the permanent curtailment of LVL production at our Roxboro, North Carolina facility. For more information, see Note 6, Curtailment of Manufacturing Facilities and Note 7, Sale of Manufacturing Facilities. (c) Depreciation and amortization for Wood Products includes $15.0 million and $55.0 million, respectively, of accelerated depreciation to fully depreciate the curtailed I-joist and LVL production assets at our Roxboro, North Carolina facility during first quarter 2020 and fourth quarter 2018, respectively. For more information, see Note 6, Curtailment of Manufacturing Facilities. (d) Capital spending in 2019 and 2018 for Building Materials Distribution includes $15.7 million and $25.5 million , respectively, for the acquisition of wholesale building material distribution locations. For more information, see Note 8, Acquisitions. December 31 2020 2019 (thousands) Assets Wood Products $ 605,359 $ 635,475 Building Materials Distribution 957,177 768,095 Corporate 403,182 289,781 Total assets $ 1,965,718 $ 1,693,351

Commitments, Legal Proceedings

Commitments, Legal Proceedings and Contingencies, and Guarantees	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments, Legal Proceedings and Contingencies, and Guarantees	Commitments, Legal Proceedings and Contingencies, and Guarantees Commitments We have commitments for leases and long-term debt that are discussed further in Note 10, Debt, and Note 11, Leases. In addition, we have purchase obligations for goods and services, capital expenditures, and raw materials entered into in the normal course of business. We are a party to a number of long-term log supply agreements. At December 31, 2020, our total obligation for log purchases under contracts with third parties was approximately $214 million based on fixed contract pricing or estimated current contractual index pricing for variable contracts. Under certain log supply agreements, we have the right to cancel or reduce our commitments in the event of a mill curtailment or shutdown. Future purchase prices under most of the variable-price agreements will be set quarterly or semiannually based on regional market prices. Our log requirements and our access to supply, as well as the cost of obtaining logs, are subject to change based on, among other things, the effect of governmental laws and regulations, our manufacturing operations not operating in the normal course of business, log availability, and the status of environmental appeals. Except for deposits required pursuant to log supply contracts, these obligations are not recorded in our consolidated financial statements until contract payment terms take effect. Legal Proceedings and Contingencies We are a party to legal proceedings that arise in the ordinary course of our business, including commercial liability claims, premises claims, environmental claims, and employment-related claims, among others. As of the date of this filing, we believe it is not reasonably possible that any of the legal actions against us will, individually or in the aggregate, have a material adverse effect on our financial position, results of operations, or cash flows. Guarantees We provide guarantees, indemnifications, and assurances to others. Boise Cascade Company and its subsidiaries (Boise Cascade Building Materials Distribution, L.L.C., and Boise Cascade Wood Products, L.L.C.) act as co-borrowers under our Revolving Credit Facility and ABL Term Loan, described in Note 10, Debt. Their obligations are guaranteed by each of our remaining domestic subsidiaries. Boise Cascade has issued $400.0 million of 4.875% senior notes due in 2030. At December 31, 2020, $400.0 million of the 2030 Notes were outstanding. The 2030 Notes are guaranteed by each of Boise Cascade Company's existing and future direct or indirect domestic subsidiaries that is a guarantor or co-borrower under our Revolving Credit Facility. See Note 10, Debt, for more information. Boise Cascade issued guarantees to a limited number of trade creditors of one or more of its principal operating subsidiaries, Boise Cascade Building Materials Distribution, L.L.C., and Boise Cascade Wood Products, L.L.C., for trade credit obligations arising in the ordinary course of the business of such operating subsidiaries. These included guarantees of obligations with respect to present and future log agreements of Boise Cascade Wood Products, L.L.C. and several facility leases entered into by Boise Cascade Building Materials Distribution, L.L.C. Boise Cascade's exposure under these agreements is limited to future log purchases and the minimum lease payment requirements under the agreements. We enter into a wide range of indemnification arrangements in the ordinary course of business. At December 31, 2020, we are not aware of any material liabilities arising from these indemnifications.

Quarterly Results of Operations

Quarterly Results of Operations (unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Quarterly Results of Operations (unaudited) 2020 First Quarter (a) Second Quarter Third Quarter (b) Fourth Quarter (c) (millions, except per-share amounts) Net sales $ 1,170.5 $ 1,242.8 $ 1,589.3 $ 1,472.2 Income from operations $ 25.5 $ 51.8 $ 158.6 $ 99.1 Net income $ 12.2 $ 33.6 $ 103.2 $ 26.0 Net income per common share – Basic $ 0.31 $ 0.85 $ 2.62 $ 0.66 Net income per common share – Diluted $ 0.31 $ 0.85 $ 2.61 $ 0.66 2019 First Quarter Second Quarter Third Quarter Fourth Quarter (millions, except per-share amounts) Net sales $ 1,042.1 $ 1,230.1 $ 1,269.5 $ 1,101.7 Income from operations $ 21.7 $ 45.1 $ 44.9 $ 24.8 Net income $ 11.4 $ 27.7 $ 27.2 $ 14.6 Net income per common share – Basic $ 0.29 $ 0.71 $ 0.70 $ 0.37 Net income per common share – Diluted $ 0.29 $ 0.71 $ 0.69 $ 0.37 __________________ (a) First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities. (b) Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt. (c) Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation [Policy Text Block]	Principles of Consolidation The consolidated financial statements include the accounts of Boise Cascade and its subsidiaries. Intercompany balances and transactions have been eliminated.
Use of Estimates [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible assets, and other long-lived assets; legal contingencies; guarantee obligations; indemnifications; assumptions used in retirement, medical, and workers' compensation benefits; assumptions used in the determination of right-of-use assets and related lease liabilities; stock-based compensation; fair value measurements; income taxes; and vendor and customer rebates, among others. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates resulting from continuing changes in the economic environment will be reflected in the consolidated financial statements in future periods.
Revenue Recognition [Policy Text Block]	Revenue Recognition Revenues are recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Wood Products Segment Our Wood Products segment manufactures EWP, consisting of laminated veneer lumber (LVL), I-joists, and laminated beams, which are structural products used in applications where extra strength and consistent quality are required, such as headers and beams. LVL is also used in the manufacture of I-joists, which are assembled by combining a vertical web of oriented strand board (OSB) with top and bottom LVL or solid wood flanges. In addition, we manufacture structural, appearance, and industrial plywood panels, and ponderosa pine lumber. Our wood products are used primarily in new residential construction, residential repair-and-remodeling markets, and light commercial construction. The majority of our wood products are sold to leading wholesalers (including our Building Materials Distribution segment), home improvement centers, retail lumberyards, and industrial converters. For EWP, plywood and veneer, byproducts, and other products, we transfer control and recognize a sale when we ship the product from our manufacturing facility to our customer. Control transfers when product is shipped because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. The amount of consideration we receive and revenue we recognize varies with changes in rebates and cash discounts we offer to our customers. See "Rebates and Cash Discounts" below. Building Materials Distribution Segment Our Building Materials Distribution segment is a leading national stocking wholesale distributor of building materials. We distribute a broad line of building materials, including OSB, plywood, and lumber (collectively referred to as commodities); general line items such as siding, composite decking, doors, metal products, insulation, and roofing; and EWP. Except for EWP, we purchase most of these building materials from third-party suppliers and market them primarily to retail lumberyards, home improvement centers, and specialty distributors that then sell the products to the final end customers, who are typically homebuilders, independent contractors, and homeowners engaged in residential construction projects. Substantially all of Building Materials Distribution's EWP is sourced from our Wood Products segment. We sell products using two primary distribution methods: warehouse sales and direct sales. Warehouse sales are distributed from our warehouses to our customers. Direct sales are shipped from the manufacturer to the customer without us taking physical possession of inventory. We report direct sales on a gross basis, that is, the amounts billed to our customers are recorded as "Sales," and inventory purchased from manufacturers are recorded as "Materials, labor, and other operating expenses (excluding depreciation)." We are the principal of direct sales because we control the inventory, as we have the ability to direct its use before it is transferred to our customers. For warehouse sales, we transfer control and recognize a sale when the customer takes physical possession of the product. Control transfers when the customer takes physical possession of the product because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. For direct sales, we transfer control and recognize a sale when the product is shipped from the manufacturer to the customer. Control transfers when product is shipped because the customer has legal title, a present obligation to pay, and risk and rewards of ownership. The amount of consideration we receive and revenue we recognize varies with changes in customer rebates and cash discounts we offer to our customers. See "Rebates and Cash Discounts" below. Rebates an d Cash Discounts Rebates are provided to our customers and our customers' customers based on the volume of their purchases, among other factors such as customer loyalty, conversion, and commitment. We provide the rebates to increase the sell-through of our products. Rebates are generally estimated based on the expected amount to be paid and recorded as a decrease in "Sales." At December 31, 2020 and 2019, we had $56.3 million and $49.4 million, respectively, of rebates payable to our customers recorded in "Accrued liabilities, Other" on our Consolidated Balance Sheets . We also estimate expected cash discounts on trade accounts receivable based on an analysis of historical experience and record cash discounts as a decrease in "Sales." We adjust our estimate of revenue at the earlier of when the probability of rebates paid and cash discounts provided ch anges or when the amounts become fixed. There have not been significant changes to our estimates of rebates, although it is reasonably possible that a change in the estimate may occur. Shipping and Handling Fees for shipping and handling charged to customers for sales transactions are included in "Sales" in our Consolidated Statements of Operations. When control over products has transferred to the customer, we have elected to recognize costs related to shipping and handling as fulfillment costs. For our Wood Products segment, costs related to shipping and handling are included in "Materials, labor, and other operating expenses (excluding depreciation)" in our Consolidated Statements of Operations. In our Wood Products segment, we view our shipping and handling costs as a cost of the manufacturing process and the movement of product to our end customers. For our Building Materials Distribution segment, costs related to shipping and handling of $177.1 million, $169.2 million, and $156.5 million for the years ended December 31, 2020, 2019, and 2018, respectively, are included in "Selling and distribution expenses" in our Consolidated Statements of Operations. In our Building Materials Distribution segment, our activities relate to the purchase and resale of finished product, and excluding shipping and handling costs from “Materials, labor, and other operating expenses (excluding depreciation)” provides us a clearer view of our operating performance and the effectiveness of our sales and purchasing functions. Other Our payment terms vary by the type of customer and the products offered. The term between invoicing and when payment is due is not significant.
Cash and Cash Equivalents [Policy Text Block]	Cash and Cash Equivalents    Cash equivalents consist of short-term investments that have a maturity of three months or less at the date of purchase. At December 31, 2020 and 2019, the majority of our cash and cash equivalents were invested in money market funds that are broadly diversified and invested in high-quality, short-duration securities, including commercial paper, certificates of deposit, U.S. government agency securities, and similar instruments. We have significant amounts of cash and cash equivalents that are in excess of federally insured limits. Though we have not experienced any losses on our cash and cash equivalents to date and we do not anticipate incurring any losses, we cannot be assured that we will not experience losses on our cash and cash equivalents.
Trade Accounts Receivables and Allowance for Doubtful Accounts [Policy Text Block]	Trade Accounts Receivables and Allowance for Doubtful Accounts Trade accounts receivable are stated at the amount we expect to collect. Trade accounts receivable do not bear interest. We make ongoing estimates relating to the collectability of our accounts receivable and maintain a reserve for estimated losses resulting from the inability of our customers to meet their financial obligations to us. At December 31, 2020 and 2019, we had $1.1 million and $0.6 million, respectively, recorded as allowances for doubtful accounts. In determining the amount of the reserve and in order to manage credit risk, we consider our historical level of credit losses, customer concentrations, and current economic trends and monitor the creditworthiness of significant customers based on ongoing credit evaluations. Our sales are principally to customers in the building products industry located in the U.S. and Canada. A significant portion of our sales are concentrated with a relatively small number of customers. In 2020, our top ten customers represented approximately 42% of sales, with one customer accounting for approximately 11% of total sales. At December 31, 2020, receivables from two customers accounted for approximately 13% and 12% of total receivables. At December 31, 2019, receivables from these two customers accounted for approximately 14% and 12% of total receivables. No other customer accounted for 10% or more of total receivables. Adjustments to the valuation allowance are charged to income. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. Although we have not experienced material credit losses in recent years, our actual future losses from uncollectable accounts may differ materially from our current estimates. As additional information becomes known, we may change our estimates. In the event we determine that a change in the reserve is appropriate, we will record a charge to "Selling and distribution expenses" in our Consolidated Statements of Operations in the period we make such a determination.
Fair Value [Policy Text Block]	Fair Value    Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy under GAAP gives the highest priority to quoted market prices (Level 1) and the lowest priority to unobservable inputs (Level 3). In general, and where applicable, we use quoted prices in active markets for identical assets or liabilities to determine fair value (Level 1). If quoted prices in active markets for identical assets or liabilities are not available to determine fair value, we use quoted prices for similar assets and liabilities or inputs that are observable either directly or indirectly (Level 2). If quoted prices for identical or similar assets are not available or are unobservable, we may use internally developed valuation models, whose inputs include bid prices, and third-party valuations utilizing underlying asset assumptions (Level 3).
Financial Instruments [Policy Text Block]	Financial Instruments Our financial instruments are cash and cash equivalents, accounts receivable, accounts payable, long-term debt, and interest rate swaps. Our cash is recorded at cost, which approximates fair value, and our cash equivalents are money market funds. As of December 31, 2020 and 2019, we held $371.8 million and $259.5 million, respectively, in money market funds that are measured at fair value on a recurring basis using Level 1 inputs. The recorded values of accounts receivable and accounts payable approximate fair values based on their short-term nature. At December 31, 2020 and 2019, the book value of our fixed-rate debt was $400.0 million and $350.0 million, respectively, and the fair value was estimated to be $432.0 million and $364.7 million, respectively. The difference between the book value and the fair value is derived from the difference between the period-end market interest rate and the stated rate of our fixed-rate, long-term debt. We estimated the fair value of our fixed-rate debt using quoted market prices of our debt in inactive markets (Level 2 inputs). The interest rate on our variable-rate debt is based on market conditions such as the London Interbank Offered Rate (LIBOR) or a base rate. Because the interest rate on the variable-rate debt is based on current market conditions, we believe that the estimated fair value of the outstanding balance on our variable-rate debt approximates book value.
Vendor Rebates and Allowances [Policy Text Block]	Rebates and allowances received from our vendors are recognized as a reduction of "Materials, labor, and other operating expenses (excluding depreciation)" when the product is sold, unless the rebates and allowances are linked to a specific incremental cost to sell a vendor's product. Amounts received from vendors that are linked to specific selling and distribution expenses are recognized as a reduction of "Selling and distribution expenses" in the period the expense is incurred.
Foreign Currency [Policy Text Block]	Foreign Currency The functional currency for our operations outside the United States is the U.S. dollar. Nonmonetary assets and liabilities and related depreciation and amortization for these foreign operations are remeasured into U.S. dollars using historical exchange rates. Monetary assets and liabilities are remeasured into U.S. dollars using the exchange rates as of the Consolidated Balance Sheet date. Revenue and expense items are remeasured into U.S. dollars using an average exchange rate prevailing during the year.
Leases [Policy Text Block]	Leases We primarily lease land, building, and equipment under operating and finance leases. We determine if an arrangement is a lease at inception and assess lease classification as either operating or finance at lease inception or upon modification. Substantially all of our leases with initial terms greater than one year are for real estate, including distribution centers, corporate headquarters, land, and other office space. Substantially all of these lease agreements have fixed payment terms based on the passage of time and are recorded in our Building Materials Distribution segment. Many of our leases include fixed escalation clauses, renewal options and/or termination options that are factored into our determination of lease term and lease payments when appropriate. Renewal options generally range from one to ten years with fixed payment terms similar to those in the original lease agreements. Some lease agreements provide us with the option to purchase the leased property at market value. Our lease agreements do not contain any residual value guarantees. Right-of-use (ROU) assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of fixed lease payments over the lease term. The current portion of our operating and finance lease liabilities are recorded in "Accrued liabilities, Other" on our Consolidated Balance Sheets. We use our estimated incremental borrowing rate, which is derived from information available at the lease commencement date, in determining the present value of lease payments. In determining our incremental borrowing rates, we give consideration to publicly available interest rates for instruments with similar characteristics, including credit rating, term, and collateralization. For purposes of determining straight-line rent expense, the lease term is calculated from the date we first take possession of the facility, including any periods of free rent and any renewal option periods we are reasonably certain of exercising. Variable lease expense generally includes reimbursement of actual costs for common area maintenance, property taxes, and insurance on leased real estate and are recorded as incurred. Most of our operating lease expense was recorded in "Selling and distribution expenses" in our Consolidated Statements of Operations. In addition, we do not separate lease and non-lease components for all of our leases.
Income Taxes [Policy Text Block]	Income Taxes We account for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and respective tax bases and operating loss and tax credit carryforwards, as measured using enacted tax rates expected to be in effect in the periods where temporary differences are expected to be realized or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We recognize deferred tax assets to the extent that we believe that these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If we determine that we would be unable to realize our deferred tax assets in the future, we would make an adjustment to the deferred tax asset valuation allowance, which would increase the provision for income taxes.
Inventory Valuation [Policy Text Block]	Inventory Valuation Inventories are valued at the lower of cost or net realizable value. Cost is based on the first-in, first-out (FIFO) method of inventory valuation or average cost. Wholesale distribution inventories include costs incurred in bringing inventory to its existing location. Manufactured inventories include costs for materials, labor, and factory overhead. Log inventories include costs to harvest and deliver the logs.
Property and Equipment [Policy Text Block]	Property and Equipment
Long-Lived Asset Impairment [Policy Text Block]	Long-Lived Asset Impairment    We review long-lived assets for impairment when events or changes in circumstances indicate that the carrying amount of assets may not be recoverable (triggering event). An impairment of long-lived assets exists when the carrying value is not recoverable through future undiscounted cash flows from operations and when the carrying value of an asset or asset group exceeds its fair value.
Goodwill and Intangible Assets [Policy Text Block]	Goodwill and Intangible Assets Impairment We maintain two reporting units for purposes of our goodwill impairment testing, Wood Products and Building Materials Distribution, which are the same as our operating segments discussed in Note 17, Segment Information. We test goodwill in each of our reporting units and intangible assets with indefinite lives for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. We also evaluate the remaining useful lives of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives are necessary.
Asset Retirement Obligations [Policy Text Block]	Asset Retirement Obligations    We recognize our asset retirement obligations in the period in which they are incurred if sufficient information is available to reasonably estimate the fair value of the obligation. Fair value estimates are determined using Level 3 inputs in the fair value hierarchy. The fair values of our asset retirement obligations are measured using expected future cash outflows discounted using the company's credit-adjusted risk-free interest rate. When we record the liability, we capitalize the cost by increasing the carrying amount of the related long-lived asset. Over time, the liability is accreted to its settlement value, and the capitalized cost is depreciated over the useful life of the related asset. Upon settlement of the liability, we will recognize a gain or loss for any difference between the settlement amount and the liability recorded.
Pension Benefits [Policy Text Block]	Pension Benefits    Several estimates and assumptions are required to record pension costs and liabilities, including discount rates, expected return on plan assets, expected rate of compensation increases, retirement and mortality rates, expected contributions, and other factors. We review and update these assumptions annually unless a plan curtailment or other event occurs requiring that we update the estimates on an interim basis.
Deferred Software Costs [Policy Text Block]	Deferred Software Costs    We defer internal-use software costs that benefit future years. These costs are amortized using the straight-line method over the expected life of the software, typically three to five years.
Self-Insurance [Policy Text Block]	Self-Insurance We are self-insured for certain losses related to workers' compensation and medical claims, general and auto liability, as well as property and business interruption losses. The expected ultimate costs for claims incurred are recognized as liabilities in the Consolidated Balance Sheets and are estimated based principally on an analysis of historical claims data and estimates of claims incurred but not reported. Losses are accrued and charged to operations when it is probable that a loss has been incurred and the amount can be reasonably estimated. We maintain third-party stop-loss insurance policies to cover these liability costs in excess of predetermined retained amounts. Costs related to the administration of the plans and related claims are expensed as incurred.
New and Recently Adopted Accounting Standards [Policy Text Block]	New and Recently Adopted Accounting Standards In March 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting , which provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. Our current contracts that reference LIBOR include certain debt instruments and interest rate swaps. The amendments are effective for eligible contract modifications subsequent to March 12, 2020, and through December 31, 2022. The adoption of this standard did not have a material effect on our financial statements, but we will assess any eligible contract modifications in the future. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to reduce complexity in accounting for income taxes. This ASU removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The updated guidance is effective for interim and annual reporting periods beginning after December 15, 2020, with early adoption permitted. We adopted this standard in first quarter of 2021 and it did not have a material effect on our financial statements. In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans . This ASU amends ASC 715 to remove disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures, and adds disclosure requirements identified as relevant related to defined benefit pension and other postretirement plans. The ASU's changes related to disclosures are part of the FASB's disclosure framework project. The updated guidance is effective retrospectively for annual reporting periods ending after December 15, 2020, with early adoption permitted. We adopted this standard in fourth quarter of 2020 and it did not have a material effect on our financial statement disclosures. There were no other accounting standards recently issued that had or are expected to have a material impact on our consolidated financial statements and associated disclosures.
Revenue , transaction price measurement, tax exclusion [Policy Text Block]	Sales, value add, and other taxes we collect concurrent with revenue-producing activities are excluded from revenue.
Commissions Expense, Policy [Policy Text Block]	We expense sales commissions when incurred as they are earned. These costs are recorded within "Selling and distribution expenses."
Compensation Related Costs [Policy Text Block]	We record compensation expense over the awards' vesting period and account for share-based award forfeitures as they occur, rather than making estimates of future forfeitures. Any shares not vested are forfeited. We recognize stock awards with only service conditions on a straight-line basis over the requisite service period.
Derivatives [Policy Text Block]	In accordance with our risk management strategy, we actively monitor our interest rate exposure and use derivative instruments from time to time to manage the related risk. We do not speculate using derivative instruments.
Segment Reporting [Policy Text Block]	Unallocated corporate costs include corporate support staff services, related assets and liabilities, and pension plan activity. Support services include, but are not limited to, information technology, human resources, finance, accounting, and legal functions. Specified expenses are allocated to the segments. For many of these allocated expenses, the related assets and liabilities remain in corporate.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Inventories [Table Text Block]	Inventories included the following (work in process is not material): December 31, December 31, (thousands) Finished goods and work in process $ 431,663 $ 413,020 Logs 35,622 45,574 Other raw materials and supplies 36,195 39,002 $ 503,480 $ 497,596
Property and Equipment [Table Text Block]	Property and equipment consisted of the following asset classes with the following general range of estimated useful lives: December 31, December 31, General Range of Estimated Useful Lives in Years (thousands) Land $ 47,099 $ 39,304 Buildings 151,718 140,008 20 - 40 Improvements 64,178 61,187 10 - 15 Mobile equipment, information technology, and office furniture 178,271 165,445 3 - 7 Machinery and equipment 687,768 666,467 7 - 12 Construction in progress 40,606 34,846 1,169,640 1,107,257 Less accumulated depreciation (708,184) (630,308) $ 461,456 $ 476,949

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income before Income Tax, Domestic and Foreign [Table Text Block]	Income before income taxes includes the following components: Year Ended December 31 2020 2019 2018 (thousands) Domestic $ 284,147 $ 105,341 $ 21,704 Foreign 2,164 2,890 398 Income before income taxes $ 286,311 $ 108,231 $ 22,102
Income Tax Provision [Table Text Block]	The income tax provision shown in the Consolidated Statements of Operations includes the following: Year Ended December 31 2020 2019 2018 (thousands) Current income tax provision Federal $ 66,401 $ 13,700 $ 6,459 State 17,434 4,574 3,126 Foreign — 7 5 Total current 83,835 18,281 9,590 Deferred income tax provision (benefit) Federal 22,321 7,430 (5,987) State 4,529 925 (2,127) Foreign 647 670 149 Total deferred 27,497 9,025 (7,965) Income tax provision $ 111,332 $ 27,306 $ 1,625
Income Tax Rate Reconciliation [Table Text Block]	The effective tax rate varies from the U.S. Federal statutory income tax rate principally due to the following: Year Ended December 31 2020 2019 2018 (thousands, except percentages) Income before income taxes $ 286,311 $ 108,231 $ 22,102 Statutory U.S. income tax rate 21.0 % 21.0 % 21.0 % Statutory tax provision $ 60,125 $ 22,728 $ 4,642 State taxes 12,267 4,390 741 Stranded tax effects of Plan Termination (a) 38,794 — — Unrecognized tax benefits 87 (178) (181) Benefit from enactment of the Tax Act (b) — — (3,806) Tax credits (712) (725) (272) Foreign rate differential 65 71 432 Share-based compensation (411) (532) (1,718) Nondeductible executive compensation 808 852 366 Meals and entertainment 340 738 886 Other (31) (38) 535 Total $ 111,332 $ 27,306 $ 1,625 Effective income tax rate 38.9 % 25.2 % 7.4 % ______________________________________ (a) In December 2020, we eliminated our qualified defined benefit pension plan (Plan Termination), as discussed in Note 12, Retirement and Benefit Plans. Prior to the Plan Termination, "Accumulated other comprehensive loss" on our Consolidated Balance Sheet included the stranded tax effects of our conversion from a limited liability company to a corporation in 2013 and the adoption of the Tax Cuts and Jobs Act (the "Tax Act") in 2017. Upon Plan Termination, these stranded tax effects of $38.8 million were required to be released into income tax expense under GAAP. (b) As of December 31, 2018, we completed our assessment of the effects of the Tax Act on our financial statements. In connection with our analysis of the Tax Act, we recorded a discrete tax benefit of $3.8 million during the year ended December 31, 2018. The $3.8 million reduction in income tax expense resulted from the remeasurement of deferred income taxes to the new federal statutory
Net Deferred Tax Assets and Liabilities [Table Text Block]	The components of our net deferred tax assets and liabilities at December 31, 2020 and 2019, are summarized as follows: December 31, 2020 December 31, 2019 (thousands) Deferred tax assets Employee benefits $ 29,258 $ 26,914 Lease liabilities 25,057 23,241 Inventories 3,711 3,358 Foreign net operating loss carryforward 1,279 1,514 Other 6,921 6,256 Deferred tax assets $ 66,226 $ 61,283 Deferred tax liabilities Property and equipment $ (45,652) $ (50,751) Right-of-use assets (23,256) (21,753) Intangible assets and other (6,823) (5,924) Other (1,298) (1,597) Deferred tax liabilities $ (77,029) $ (80,025) Total deferred tax liabilities, net $ (10,803) $ (18,742)
Unrecognized Tax Benefits Roll Forward [Table Text Block]	The following table summarizes the changes related to our gross unrecognized tax benefits excluding interest and penalties: 2020 2019 2018 (thousands) Balance as of January 1 $ 1,685 $ 1,850 $ 2,083 Increases related to prior years' tax positions 97 — 13 Increases related to current years' tax positions 89 53 — Decreases related to prior years' tax positions — — (43) Lapse of statute of limitations (91) (218) (203) Balance as of December 31 $ 1,780 $ 1,685 $ 1,850

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Income Per Common Share [Table Text Block]	The following table sets forth the computation of basic and diluted net income per common share: Year Ended December 31 2020 2019 2018 (thousands, except per-share data) Net income $ 174,979 $ 80,925 $ 20,477 Weighted average common shares outstanding during the period (for basic calculation) 39,277 39,039 38,932 Dilutive effect of other potential common shares 154 203 455 Weighted average common shares and potential common shares (for diluted calculation) 39,431 39,242 39,387 Net income per common share - Basic $ 4.45 $ 2.07 $ 0.53 Net income per common share - Diluted $ 4.44 $ 2.06 $ 0.52

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill [Table Text Block]	The carrying amount of our goodwill by segment is as follows: Building Wood Products Total (thousands) Balance at December 31, 2020 and 2019 $ 11,792 $ 48,590 $ 60,382
Schedule of Indefinite-Lived Intangible Assets [Table Text Block]	Intangible assets consisted of the following: December 31, 2020 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (4,776) 7,674 $ 21,350 $ (4,776) $ 16,574 December 31, 2019 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (3,553) 8,897 $ 21,350 $ (3,553) $ 17,797
Schedule of Finite-Lived Intangible Assets [Table Text Block]	Intangible assets consisted of the following: December 31, 2020 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (4,776) 7,674 $ 21,350 $ (4,776) $ 16,574 December 31, 2019 Gross Carrying Accumulated Net Carrying (thousands) Trade names and trademarks $ 8,900 $ — $ 8,900 Customer relationships 12,450 (3,553) 8,897 $ 21,350 $ (3,553) $ 17,797

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt [Table Text Block]	Long-term debt consisted of the following: December 31, December 31, (thousands) Asset-based revolving credit facility due 2025 $ — $ — Asset-based credit facility term loan due 2025 50,000 50,000 Term loan due 2026 — 45,000 4.875% senior notes due 2030 400,000 — 5.625% senior notes due 2024 — 350,000 Deferred financing costs (6,208) (4,456) Long-term debt $ 443,792 $ 440,544
Schedule of Maturities of Long-term Debt [Table Text Block]	At December 31, 2020, the maturities for the aggregate amount of long-term debt outstanding were as follows (in thousands): 2021 $ — 2022 — 2023 — 2024 — 2025 50,000 Thereafter 400,000

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Costs [Table Text Block]	The components of lease expense were as follows: Year Ended December 31 2020 2019 (thousands) Operating lease cost $ 13,339 $ 13,541 Finance lease cost Amortization of right-of-use assets 2,210 1,616 Interest on lease liabilities 2,271 1,899 Variable lease cost 2,967 2,645 Short-term lease cost 4,115 4,614 Sublease income (140) (540) Total lease cost $ 24,762 $ 23,775
Lease Supplemental Cash Flow [Table Text Block]	Supplemental cash flow information related to leases was as follows: Year Ended December 31 2020 2019 (thousands) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 13,018 $ 13,508 Operating cash flows from finance leases 2,271 1,862 Financing cash flows from finance leases 1,307 783 Right-of-use assets obtained in exchange for lease obligations Operating leases 8,310 4,211 Finance leases 9,969 2,637
Lessee, Weighted-average Term and Discount Rate [Table Text Block]	Other information related to leases was as follows: December 31, 2020 December 31, 2019 Weighted-average remaining lease term (years) Operating leases 8 8 Finance leases 15 14 Weighted-average discount rate Operating leases (a) 6.4 % 6.5 % Finance leases 7.7 % 8.5 % ___________________________________ (a) Upon adoption of the new lease standard, discount rates used for existing leases were established at January 1, 2019.
Minimum Lease Payment Requirements for Operating Lease Liability [Table Text Block]	As of December 31, 2020, our minimum lease payment requirements for noncancelable operating and finance leases are as follows: Operating Leases Finance Leases (thousands) 2021 $ 13,593 $ 3,924 2022 13,024 3,930 2023 12,073 3,970 2024 11,189 3,967 2025 9,448 3,607 Thereafter 25,545 37,801 Total future minimum lease payments 84,872 57,199 Less: interest (18,945) (24,035) Total lease obligations 65,927 33,164 Less: current obligations (9,926) (1,557) Long-term lease obligations $ 56,001 $ 31,607 As of December 31, 2020, the minimum lease payment amount for leases signed but not yet commenced was $7.3 million.
Minimum Lease Payment Requirements for Finance Lease Liability [Table Text Block]	As of December 31, 2020, our minimum lease payment requirements for noncancelable operating and finance leases are as follows: Operating Leases Finance Leases (thousands) 2021 $ 13,593 $ 3,924 2022 13,024 3,930 2023 12,073 3,970 2024 11,189 3,967 2025 9,448 3,607 Thereafter 25,545 37,801 Total future minimum lease payments 84,872 57,199 Less: interest (18,945) (24,035) Total lease obligations 65,927 33,164 Less: current obligations (9,926) (1,557) Long-term lease obligations $ 56,001 $ 31,607 As of December 31, 2020, the minimum lease payment amount for leases signed but not yet commenced was $7.3 million.

Retirement and Benefit Plans (T

Retirement and Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Defined Benefit Obligations and Funded Status [Table Text Block]	The following table, which includes only company-sponsored defined benefit plans, reconciles the beginning and ending balances of our projected benefit obligation and fair value of plan assets. We recognize the underfunded status of our defined benefit pension plans on our Consolidated Balance Sheets. We recognize changes in funded status in the year changes occur through other comprehensive income (loss). December 31 2020 2019 (thousands) Change in benefit obligation Benefit obligation at beginning of year $ 192,061 $ 176,852 Service cost 668 647 Interest cost 5,893 7,210 Actuarial loss 18,605 29,065 Group annuity transactions (a) (76,650) (19,848) Benefits paid (b) (135,690) (1,865) Benefit obligation at end of year 4,887 192,061 Change in plan assets Fair value of plan assets at beginning of year 168,651 154,801 Actual return on plan assets 30,930 29,769 Employer contributions 12,759 5,238 Group annuity transactions (a) (76,650) (19,292) Benefits paid (b) (135,690) (1,865) Fair value of plan assets at end of year — 168,651 Underfunded status $ (4,887) $ (23,410) Amounts recognized on our Consolidated Balance Sheets Current liabilities $ (367) $ (878) Noncurrent liabilities (4,520) (22,532) Net liability $ (4,887) $ (23,410) Amounts recognized in accumulated other comprehensive loss Net actuarial loss $ 1,443 $ 15,332 Prior service cost — — Net loss recognized $ 1,443 $ 15,332 ______________________________________ (a) See Defined Benefits Plans above for description of group annuity transactions. (b) See Defined Benefits Plans above for description of lump-sum payments.
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	The components of net periodic benefit cost and other amounts recognized in other comprehensive (income) loss are as follows: Year Ended December 31 2020 2019 2018 (thousands) Net periodic benefit cost Service cost $ 668 $ 647 $ 794 Interest cost 5,893 7,210 11,344 Expected return on plan assets (5,493) (5,903) (11,097) Amortization of actuarial (gain) loss 807 (175) 1,497 Plan settlement expense (a) 6,250 1,342 23,255 Net periodic benefit cost 8,125 3,121 25,793 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Net actuarial (gain) loss (6,832) 4,642 (14,178) Amortization of actuarial gain (loss) (807) 175 (1,497) Effect of settlements (6,250) (1,342) (23,255) Total recognized in other comprehensive (income) loss (13,889) 3,475 (38,930) Total recognized in net periodic cost and other comprehensive (income) loss $ (5,764) $ 6,596 $ (13,137) ______________________________________
Schedule of Net Benefit Costs [Table Text Block]	The components of net periodic benefit cost and other amounts recognized in other comprehensive (income) loss are as follows: Year Ended December 31 2020 2019 2018 (thousands) Net periodic benefit cost Service cost $ 668 $ 647 $ 794 Interest cost 5,893 7,210 11,344 Expected return on plan assets (5,493) (5,903) (11,097) Amortization of actuarial (gain) loss 807 (175) 1,497 Plan settlement expense (a) 6,250 1,342 23,255 Net periodic benefit cost 8,125 3,121 25,793 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Net actuarial (gain) loss (6,832) 4,642 (14,178) Amortization of actuarial gain (loss) (807) 175 (1,497) Effect of settlements (6,250) (1,342) (23,255) Total recognized in other comprehensive (income) loss (13,889) 3,475 (38,930) Total recognized in net periodic cost and other comprehensive (income) loss $ (5,764) $ 6,596 $ (13,137) ______________________________________
Schedule of Assumptions Used [Table Text Block]	The following table presents the assumptions used in the measurement of our benefit obligations: December 31 2020 2019 Weighted average assumptions Discount rate 2.00 % 3.10 % Rate of compensation increases (a) — % — % The following table presents the assumptions used in the measurement of net periodic benefit cost: December 31 2020 2019 2018 (b) Weighted average assumptions Discount rate 3.10 % 4.15 % 3.95 % / 4.05 % / 3.40 % Expected long-term rate of return on plan assets 3.50 % 3.85 % 3.85 % / 4.50 % / 4.75 % Rate of compensation increases (a) — % — % — % _______________________________________ (a) Pension benefits for all salaried employees are frozen, resulting in an assumption for the rate of compensation increase of zero.
Schedule of Allocation of Plan Assets [Table Text Block]	The following table sets forth by level, within the fair value hierarchy, the pension plan assets, by major asset category, at fair value at December 31, 2019: December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Total (thousands) Fixed-income securities (b) $ — $ 152,530 $ — $ 152,530 Multi-asset class fund (c) — 16,361 — 16,361 Total investments at fair value $ — $ 168,891 $ — 168,891 Receivables and accrued expenses, net (240) Fair value of plan assets $ 168,651 _______________________________________ (a) Securities represent common collective trusts managed and valued by Russell Trust Company, the administrator of the funds. While the underlying assets are actively traded on an exchange, the funds are not. The investments in equity and fixed-income securities are considered to have a readily determinable fair value because the fair value per share (unit) is determined and published and is the basis for current transactions. We had the ability to redeem these securities with a 1 day notice. (b) Invested in the Russell Long Duration Fixed Income Fund, which is designed to provide current income and capital appreciation through diversified strategies including sector rotation, modest interest rate timing, security selection, and tactical use of high-yield, emerging market bonds and other non-index securities. In addition, our investments in this category included the Russell 14 Year LDI Fixed Income Fund. We also were invested in the Russell 8 Year LDI Fixed Income Fund. These LDI funds invest primarily in investment grade bonds that closely match those found in discount rate curves used to value U.S. pension liabilities and seeks to provide additional incremental return through modest interest rate timing, security selection, and tactical use of non-credit sectors. In addition, our investments in this category included Russell STRIPS Fixed Income Funds with duration profiles of 10, 15, and 28 years. These funds invest in a subset of the STRIPS universe with a similar duration profile as their respective Bloomberg Barclays U.S. STRIPS Index. (c) Invested in the Russell Multi-Asset Core Plus Fund, which is designed to provide long-term growth by providing a diversified portfolio of investments that has an overall strategic allocation of 75% global equity, 15% marketable real assets, and 10% global fixed income.
Schedule of Expected Benefit Payments [Table Text Block]	Nonqualified pension benefit payments are paid by the company. The following benefit payments are expected to be paid to nonqualified plan participants (in thousands): 2021 $ 367 2022 380 2023 382 2024 368 2025 314 Years 2026-2030 1,373

Long-Term Incentive Compensat_2

Long-Term Incentive Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Compensation Related Costs [Abstract]
Schedule of Nonvested Share Activity [Table Text Block]	The following summarizes the activity of our PSUs and RSUs awarded under our incentive plan for the year ended December 31, 2020: PSUs RSUs Number of shares Weighted Average Grant-Date Fair Value Number of shares Weighted Average Grant-Date Fair Value Outstanding, December 31, 2019 295,347 $ 31.09 257,564 $ 31.14 Granted 94,850 36.45 125,716 36.45 Performance condition adjustment (a) (6,989) 29.48 — — Vested (162,622) 28.93 (143,807) 30.88 Forfeited (24,246) 32.57 (26,707) 32.82 Outstanding, December 31, 2020 196,340 $ 35.34 212,766 $ 34.24 __________________ (a) Represents total PSUs forfeited during the year ended December 31, 2020, related to the 2019 performance condition adjustment described above.
Stock-based compensation expense recognized [Table Text Block]	Total stock-based compensation recognized from PSUs and RSUs, net of forfeitures, was as follows: Year Ended December 31 2020 2019 2018 (thousands) PSUs $ 3,795 $ 3,340 $ 4,005 RSUs 4,025 4,633 4,826 Total $ 7,820 $ 7,973 $ 8,831

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Dividends Declared [Table Text Block]	Our board of directors declared and paid the following dividends during each of the respective quarters for the years ended December 31, 2020, 2019, and 2018: Dividends Per Share Amount Paid 2020 (in thousands) First Quarter (a) $ 0.10 $ 4,645 Second Quarter 0.10 3,917 Third Quarter (b) 1.70 3,991 Fourth Quarter (b) 0.10 66,642 Total $ 2.00 $ 79,195 2019 First Quarter (a) $ 0.09 $ 4,053 Second Quarter 0.09 3,509 Third Quarter 0.09 3,508 Fourth Quarter (c) 1.10 42,884 Total $ 1.37 $ 53,954 2018 First Quarter (a) $ 0.07 $ 2,758 Second Quarter 0.07 2,723 Third Quarter (c) 1.07 41,632 Fourth Quarter 0.09 3,502 Total $ 1.30 $ 50,615 __________________ (a) Includes payments of dividend equivalents on RSUs and PSUs which vested in first quarter of each year. (b) During third quarter 2020, our board of directors declared a supplemental dividend of $1.60 per share on our common stock, which was paid in fourth quarter 2020.
Changes in Accumulated Other Comprehensive Loss [Table Text Block]	Changes in accumulated other comprehensive loss are as follows: Changes in Accumulated Other Comprehensive Loss Year Ended December 31 2020 2019 2018 (thousands) Beginning Balance, net of taxes $ (50,248) $ (47,652) $ (76,702) Net actuarial gain (loss), before taxes 6,832 (4,642) 14,178 Amortization of actuarial (gain) loss, before taxes (a) 807 (175) 1,497 Effect of settlements, before taxes (a) 6,250 1,342 23,255 Income taxes (b) 35,281 879 (9,880) Ending Balance, net of taxes $ (1,078) $ (50,248) $ (47,652) ___________________________________ (a) Represents amounts reclassified from accumulated other comprehensive loss. These amounts are included in the computation of net periodic pension cost. For additional information, see Note 12, Retirement and Benefit Plans. (b) For the year ended December 31, 2020, income taxes include $38.8 million related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Sales by product line [Table Text Block]	Wood Products and Building Materials Distribution segment sales to external customers, including related parties, by product line are as follows: Year Ended December 31 2020 2019 2018 (millions) Wood Products (a) LVL $ 18.4 $ 39.5 $ 42.2 I-joists 7.3 22.1 29.3 Other engineered wood products 23.9 26.8 25.3 Plywood and veneer 332.7 255.1 336.2 Lumber (b) 54.7 52.5 86.0 Byproducts 68.6 75.1 87.3 Particleboard (b) — — 37.5 Other 17.1 34.7 63.9 522.8 505.7 707.7 Building Materials Distribution Commodity 2,309.9 1,725.4 2,070.1 General line 1,762.3 1,580.7 1,421.5 Engineered wood products 879.9 831.6 796.0 4,952.0 4,137.7 4,287.6 $ 5,474.8 $ 4,643.4 $ 4,995.3 ___________________________________ (a) Amounts represent sales to external customers. Sales are calculated after intersegment sales eliminations to our Building Materials Distribution segment, as well as the cost of EWP rebates and sales allowances provided at various stages of the supply chain (including distributors, retail lumberyards, and homebuilders). For the years ended December 31, 2020, 2019, and 2018, approximately 80%, 77%, and 74%, respectively, of Wood Products' EWP sales volumes were to our Building Materials Distribution segment. (b) In fourth quarter 2018, we sold two lumber mills and our particleboard plant located in Northeast Oregon. For additional information, see Note 7, Sale of Manufacturing Facilities.
Segment information [Table Text Block]	An analysis of our operations by segment is as follows: Year Ended December 31 2020 2019 2018 (thousands) Net sales by segment Wood Products $ 1,323,901 $ 1,275,167 $ 1,533,270 Building Materials Distribution 4,952,018 4,137,719 4,287,702 Intersegment eliminations (a) (801,081) (769,482) (825,682) Total net sales $ 5,474,838 $ 4,643,404 $ 4,995,290 Segment operating income (loss) Wood Products (b) $ 127,720 $ 54,197 $ (10,022) Building Materials Distribution 247,494 116,236 112,510 Total segment operating income 375,214 170,433 102,488 Unallocated corporate costs (40,185) (33,974) (30,450) Income from operations $ 335,029 $ 136,459 $ 72,038 Depreciation and amortization Wood Products (c) $ 71,141 $ 57,671 $ 126,989 Building Materials Distribution 22,460 20,769 18,280 Corporate 1,568 1,701 1,568 Total depreciation and amortization $ 95,169 $ 80,141 $ 146,837 Capital expenditures Wood Products $ 38,230 $ 53,460 $ 53,392 Building Materials Distribution (d) 39,976 40,722 51,306 Corporate 1,223 4,214 771 Total capital expenditures $ 79,429 $ 98,396 $ 105,469 __________________ (a) Primarily represents intersegment sales from our Wood Products segment to our Building Materials Distribution segment. During 2020, 2019, and 2018, approximately 61%, 60%, and 54%, respectively, of Wood Products' overall sales were to our Building Materials Distribution segment. (b) Wood Products segment operating income for the year ended December 31, 2020, includes $15.0 million of accelerated depreciation and $1.7 million of other closure-related costs due to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility. In addition, Wood Products segment operating loss for the year ended December 31, 2018, includes pre-tax facility impairment and sales related losses of $35.5 million, as well as $57.8 million of accelerated depreciation and other curtailment costs related to the permanent curtailment of LVL production at our Roxboro, North Carolina facility. For more information, see Note 6, Curtailment of Manufacturing Facilities and Note 7, Sale of Manufacturing Facilities. (c) Depreciation and amortization for Wood Products includes $15.0 million and $55.0 million, respectively, of accelerated depreciation to fully depreciate the curtailed I-joist and LVL production assets at our Roxboro, North Carolina facility during first quarter 2020 and fourth quarter 2018, respectively. For more information, see Note 6, Curtailment of Manufacturing Facilities. (d) Capital spending in 2019 and 2018 for Building Materials Distribution includes $15.7 million and $25.5 million , respectively, for the acquisition of wholesale building material distribution locations. For more information, see Note 8, Acquisitions. December 31 2020 2019 (thousands) Assets Wood Products $ 605,359 $ 635,475 Building Materials Distribution 957,177 768,095 Corporate 403,182 289,781 Total assets $ 1,965,718 $ 1,693,351

Quarterly Results of Operatio_2

Quarterly Results of Operations (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (unaudited) [Table Text Block]	2020 First Quarter (a) Second Quarter Third Quarter (b) Fourth Quarter (c) (millions, except per-share amounts) Net sales $ 1,170.5 $ 1,242.8 $ 1,589.3 $ 1,472.2 Income from operations $ 25.5 $ 51.8 $ 158.6 $ 99.1 Net income $ 12.2 $ 33.6 $ 103.2 $ 26.0 Net income per common share – Basic $ 0.31 $ 0.85 $ 2.62 $ 0.66 Net income per common share – Diluted $ 0.31 $ 0.85 $ 2.61 $ 0.66 2019 First Quarter Second Quarter Third Quarter Fourth Quarter (millions, except per-share amounts) Net sales $ 1,042.1 $ 1,230.1 $ 1,269.5 $ 1,101.7 Income from operations $ 21.7 $ 45.1 $ 44.9 $ 24.8 Net income $ 11.4 $ 27.7 $ 27.2 $ 14.6 Net income per common share – Basic $ 0.29 $ 0.71 $ 0.70 $ 0.37 Net income per common share – Diluted $ 0.29 $ 0.71 $ 0.69 $ 0.37 __________________ (a) First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities. (b) Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt. (c) Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.

Nature of Operations and Consol

Nature of Operations and Consolidation (Details)	12 Months Ended
	Dec. 31, 2020segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Reportable Segments	2

Summary of Significant Accoun_4

Summary of Significant Accounting Policies:Trade Accounts Receivables and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Trade Accounts Receivables and Allowance for Doubtful Accounts
Trade receivables, allowances	$ 1,111	$ 591
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Top Ten Customers [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	42.00%
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Customer One [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Customer Two [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	13.00%	14.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Customer One [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	12.00%	12.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies:Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Reported Value Measurement [Member] | 4.875% Senior Notes Due 2030 [Member]
Financial Instruments [Line Items]
Fixed-rate debt	$ 400
Reported Value Measurement [Member] | 5.625% Senior Notes Due 2024 [Member]
Financial Instruments [Line Items]
Fixed-rate debt		$ 350
Level 2 [Member] | Estimate of Fair Value Measurement [Member] | 4.875% Senior Notes Due 2030 [Member]
Financial Instruments [Line Items]
Fixed-rate debt	432
Level 2 [Member] | Estimate of Fair Value Measurement [Member] | 5.625% Senior Notes Due 2024 [Member]
Financial Instruments [Line Items]
Fixed-rate debt		364.7
Money Market Funds [Member] | Fair Value, Recurring [Member] | Level 1 [Member]
Financial Instruments [Line Items]
Cash equivalents, fair value	$ 371.8	$ 259.5

Summary of Significant Accoun_6

Summary of Significant Accounting Policies:Vendor Rebates and Allowances (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Vendor Rebates and Allowances	$ 9.9	$ 9.2

Summary of Significant Accoun_7

Summary of Significant Accounting Policies: Leases (Details)	12 Months Ended
	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Lease Term, Minimum Initial Term of Real Estate Leases	1 year
Real Estate Leases, Cancellation Notice, Latest Notice	30 days
Real Estate Leases, Cancellation Notice, Earliest Notice	90 days
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	1 year
Capitalized Computer Software, Amortization Period	three
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	10 years
Capitalized Computer Software, Amortization Period	five

Summary of Significant Accoun_8

Summary of Significant Accounting Policies:Inventory Valuation (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory, Net [Abstract]
Finished goods and work in process	$ 431,663	$ 413,020
Logs	35,622	45,574
Other raw materials and supplies	36,195	39,002
Inventories	$ 503,480	$ 497,596

Summary of Significant Accoun_9

Summary of Significant Accounting Policies:Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,169,640	$ 1,107,257
Less accumulated depreciation	(708,184)	(630,308)
Property and equipment, net	461,456	476,949
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	47,099	39,304
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 151,718	140,008
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 64,178	61,187
Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	15 years
Mobile equipment, information technology, and office furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 178,271	165,445
Mobile equipment, information technology, and office furniture [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Mobile equipment, information technology, and office furniture [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	7 years
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 687,768	666,467
Machinery and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	7 years
Machinery and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	12 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 40,606	$ 34,846

Summary of Significant Accou_10

Summary of Significant Accounting Policies:Goodwill Impairment (Details)	12 Months Ended
	Dec. 31, 2020Units
Goodwill and Intangible Assets Disclosure [Abstract]
Number of Reporting Units	2

Summary of Significant Accou_11

Summary of Significant Accounting Policies:Asset Retirement Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	$ 2.3	$ 2.2

Summary of Significant Accou_12

Summary of Significant Accounting Policies:Deferred Software Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capitalized Computer Software [Line Items]
Capitalized Computer Software, Net	$ 4.1	$ 4.6
Capitalized Computer Software, Amortization	$ 1.9	$ 2	$ 2
Minimum [Member]
Capitalized Computer Software [Line Items]
Capitalized Computer Software Amortization Period (in years)	three
Maximum [Member]
Capitalized Computer Software [Line Items]
Capitalized Computer Software Amortization Period (in years)	five

Summary of Significant Accou_13

Summary of Significant Accounting Policies:Labor Concentration and Unions (Details)	12 Months Ended
	Dec. 31, 2020employeeInteger6
Concentration Risk [Line Items]
Entity Number of Employees | employee	5,970
Number of collective bargaining arrangements | Integer6	10
Number of Collective Bargaining Agreements Set to Expire Within One Year | Integer6	2
Workforce Subject to Collective Bargaining Arrangements [Member] | Unionized Employees Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	22.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]
Concentration Risk [Line Items]
Entity Number of Employees | employee	740

Summary of Significant Accou_14

Summary of Significant Accounting Policies:Self-Insurance (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Self Insurance Liabilities, Current	$ 9.5	$ 9.9
Self Insurance Liabilities, Noncurrent	$ 10	$ 10

Revenues Revenue Recognition (D

Revenues Revenue Recognition (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)Distribution	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Revenue from External Customer [Line Items]
Customer Rebates and Allowances	$ 56.3	$ 49.4
Building Materials Distribution [Member]
Revenue from External Customer [Line Items]
Number of Primary Distribution Methods | Distribution	2
Building Materials Distribution [Member] | Shipping and Handling [Member]
Revenue from External Customer [Line Items]
Cost of Goods and Services Sold	$ 177.1	$ 169.2	$ 156.5

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Pretax income (loss) from domestic and foreign sources [Abstract]
Domestic		$ 284,147		$ 105,341	$ 21,704
Foreign		2,164		2,890	398
Income before income taxes		286,311		108,231	22,102
Deferred income tax provision (benefit) [Abstract]
Federal		66,401		13,700	6,459
State		17,434		4,574	3,126
Foreign		0		7	5
Total current		83,835		18,281	9,590
Federal		22,321		7,430	(5,987)
State		4,529		925	(2,127)
Foreign		647		670	149
Total deferred		27,497		9,025	(7,965)
Income tax provision		111,332		27,306	1,625
Income Tax Rate Reconciliation [Abstract]
Income before income taxes		$ 286,311		$ 108,231	$ 22,102
Statutory U.S. income tax rate (as a percent)		21.00%		21.00%	21.00%		35.00%
Statutory tax provision		$ 60,125		$ 22,728	$ 4,642
State taxes		12,267		4,390	741
Stranded tax effects of Plan Termination	$ 38,800	38,794	[1]	0	0
Unrecognized tax benefits		87		(178)	(181)
Benefit from enactment of the Tax Act		0		0	(3,806)	[2]
Tax credits		(712)		(725)	(272)
Foreign rate differential		65		71	432
Share-based compensation		(411)		(532)	(1,718)
Nondeductible executive compensation		808		852	366
Meals and entertainment		340		738	886
Other		(31)		(38)	535
Income tax provision		$ 111,332		$ 27,306	$ 1,625
Effective income tax rate (as a percent)		38.90%		25.20%	7.40%
Income taxes paid (refunds), net		$ 75,100		$ (1,400)	$ 14,500
Deferred tax assets [Abstract]
Employee benefits	29,258	29,258		26,914
Lease Liabilities	25,057	25,057		23,241
Inventories	3,711	3,711		3,358
Foreign net operating loss carryforward	1,279	1,279		1,514
Other	6,921	6,921		6,256
Net deferred tax assets	66,226	66,226		61,283
Deferred tax liabilities [Abstract]
Property and equipment	(45,652)	(45,652)		(50,751)
Right-of-use assets	(23,256)	(23,256)		(21,753)
Intangible assets and other	(6,823)	(6,823)		(5,924)
Other	(1,298)	(1,298)		(1,597)
Deferred tax liabilities	(77,029)	(77,029)		(80,025)
Total deferred tax liabilities, net	(10,803)	(10,803)		(18,742)
Reconciliation of unrecognized tax benefits, roll forward
Balance as of January 1		1,685		1,850	2,083
Increases related to prior years' tax positions		97		0	13
Increases related to current years' tax positions		89		53	0
Decreases related to prior years' tax positions		0		0	(43)
Lapse of statute of limitations		(91)		(218)	(203)
Balance as of December 31	1,780	1,780		1,685	1,850		$ 2,083
Unrecognized tax benefits that would impact tax rate	1,800	1,800		$ 1,700	$ 1,800
State and Local Jurisdiction [Member]
Deferred tax liabilities [Abstract]
State income tax credits, subject to expiration	1,300	1,300
CANADA | Subsidiaries [Member]
Deferred tax liabilities [Abstract]
Foreign net operating loss carryforwards, subject to expiration	$ 9,900	$ 9,900
[1]	In December 2020, we eliminated our qualified defined benefit pension plan (Plan Termination), as discussed in Note 12, Retirement and Benefit Plans. Prior to the Plan Termination, "Accumulated other comprehensive loss" on our Consolidated Balance Sheet included the stranded tax effects of our conversion from a limited liability company to a corporation in 2013 and the adoption of the Tax Cuts and Jobs Act (the "Tax Act") in 2017. Upon Plan Termination, these stranded tax effects of $38.8 million were required to be released into income tax expense under GAAP.
[2]	As of December 31, 2018, we completed our assessment of the effects of the Tax Act on our financial statements. In connection with our analysis of the Tax Act, we recorded a discrete tax benefit of $3.8 million during the year ended December 31, 2018. The $3.8 million reduction in income tax expense resulted from the remeasurement of deferred income taxes to the new federal statutory rate of 21%, which mostly related to a $20.0 million discretionary pension contribution made during 2018, for which we received a tax deduction at the 2017 federal income tax rate of 35%.

Net Income Per Common Share (De

Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended											12 Months Ended
	Dec. 31, 2020	[1]	Sep. 30, 2020	[2]	Jun. 30, 2020	Mar. 31, 2020	[3]	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Income	$ 26,000		$ 103,200		$ 33,600	$ 12,200		$ 14,600	$ 27,200	$ 27,700	$ 11,400	$ 174,979	$ 80,925	$ 20,477
Computation of basic and diluted net income per common share
Weighted average common shares outstanding during the period (for basic calculation)												39,277	39,039	38,932
Dilutive effect of other potential common shares												154	203	455
Weighted average common shares and potential common shares (for diluted calculation)												39,431	39,242	39,387
Net income per common share - Basic	$ 0.66		$ 2.62		$ 0.85	$ 0.31		$ 0.37	$ 0.70	$ 0.71	$ 0.29	$ 4.45	$ 2.07	$ 0.53
Net income (loss) per common share – Diluted	$ 0.66		$ 2.61		$ 0.85	$ 0.31		$ 0.37	$ 0.69	$ 0.71	$ 0.29	$ 4.44	$ 2.06	$ 0.52
Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive stock awards												0	100	100
[1]	Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.
[2]	Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt.
[3]	First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities.

Curtailment of Manufacturing _2

Curtailment of Manufacturing Facilities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Feb. 20, 2020	Dec. 31, 2018	Nov. 02, 2018	Dec. 31, 2020	Dec. 31, 2018
Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Activities, Initiation Date		Feb. 20, 2020
Restructuring and Related Activities, Completion Date	Mar. 31, 2020
Accelerated depreciation					$ 15
Curtailment of I-joist Production at Roxboro, NC Facility [Member] | Loss on curtailment of facility [Member]
Restructuring Cost and Reserve [Line Items]
Other closure related costs					$ 1.7
Curtailment of LVL Production at Roxboro, NC Facility [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Activities, Initiation Date				Nov. 2, 2018
Restructuring and Related Activities, Completion Date			Dec. 31, 2018
Accelerated depreciation						$ 55
Curtailment of LVL Production at Roxboro, NC Facility [Member] | Loss on sale and curtailment of facilities [Member]
Restructuring Cost and Reserve [Line Items]
Other closure related costs						2.6
Severance-related expenses						$ 0.2

Sales of Manufacturing Faciliti

Sales of Manufacturing Facilities:Sale of Assets (Details) - USD ($) $ in Thousands	Mar. 01, 2019	Nov. 02, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of facilities			$ 0	$ 2,493	$ 15,003
Loss on sale and curtailment of facilities			$ 1,707	0	38,314
Agreement to Sell Hardwood Facility at Moncure, North Carolina [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Revenue				5,500	32,700
Disposal Group, Operating Loss				$ (1,400)	(7,000)
Proceeds from sale of facilities	$ 2,500
Agreement to Sell Hardwood Facility at Moncure, North Carolina [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Loss on sale and curtailment of facilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale and curtailment of facilities					24,000
Agreement With Woodgrain Millwork for Two Lumber Mills and a Particleboard Plant In Northeast Oregon [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Revenue					74,100
Disposal Group, Operating Loss					(200)
Proceeds from sale of facilities		$ 15,000
Agreement With Woodgrain Millwork for Two Lumber Mills and a Particleboard Plant In Northeast Oregon [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Loss on sale and curtailment of facilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale and curtailment of facilities					$ 11,500

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
BMD Birmingham Acquisition [Member]
Business Acquisition [Line Items]
Purchase price of acquisitions	$ 15.7
Purchase price, post-closing adjustment	$ 0.1
Nashville, Medford, and Cincinnati BMD facilities [Member]
Business Acquisition [Line Items]
Purchase price of acquisitions		$ 25.5

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Details) $ in Thousands	Dec. 31, 2020USD ($)
Goodwill [Abstract]
Balance at December 31, 2019	$ 60,382
Balance at December 31, 2020	60,382
Building Materials Distribution [Member]
Goodwill [Abstract]
Balance at December 31, 2019	11,792
Balance at December 31, 2020	11,792
Wood Products [Member]
Goodwill [Abstract]
Balance at December 31, 2019	48,590
Balance at December 31, 2020	$ 48,590

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible Amortization Expense, Next Twelve Months	$ 1,200
Intangible Amortization Expense, Year Two	1,200
Intangible Amortization Expense, Year Three	1,200
Intangible Amortization Expense, Year Four	1,200
Intangible Amortization Expense, Year Five	1,200
Customer relationships, Accumulated amortization	(4,776)	$ (3,553)
Intangible assets [Abstract]
Intangible Assets, Gross (Excluding Goodwill)	21,350	21,350
Intangible Assets, Net (Excluding Goodwill)	16,574	17,797
Trademarks and Trade Names [Member]
Indefinite-lived Intangible Assets [Line Items]
Trade names and trademarks, Gross carrying amount	$ 8,900	8,900
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-Lived Intangible Assets, Gross	$ 12,450	12,450
Customer relationships, Accumulated amortization	(4,776)	(3,553)
Finite-Lived Intangible Assets, Net	$ 7,674	$ 8,897

Debt_Summary Table (Details)

Debt:Summary Table (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Deferred financing costs	$ (6,208)	$ (4,456)
Long-term debt	443,792	440,544
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0	0
ABL Term Loan Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	50,000	50,000
Long-term debt	50,000
Term Loan Due 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0	45,000
4.875% Senior Notes Due 2030 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	400,000	0
5.625% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 0	$ 350,000

Debt_Five Year Maturity Table (

Debt:Five Year Maturity Table (Details) $ in Thousands	Dec. 31, 2020USD ($)
Debt Disclosure [Abstract]
2021	$ 0
2022	0
2023	0
2024	0
2025	50,000
Thereafter	$ 400,000

Debt_Asset-Based Credit Facilit

Debt:Asset-Based Credit Facility (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 13, 2020	Dec. 31, 2019	May 15, 2015
AssetBasedCreditFacility [Member]
Line of Credit Facility [Line Items]
Fixed charge coverage ratio requirement, if availability falls below 10% of aggregate lending commitments (as a percent)	100.00%
Threshold of availability as a percentage of aggregate lending commitments, below which 1:1 fixed charge coverage ratio must be met	10.00%
Threshold of availability, below which 1:1 fixed charge coverage ratio must be met	$ 35
Current availability	$ 345.2
Dividend restriction, single threshold, percentage of aggregate Revolver Commitments	25.00%
Dividend restriction, combination thresholds, percentage of aggregate Revolver Commitments	15.00%
Dividend restriction, combination thresholds, fixed-charge coverage ratio (as a percent)	100.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 350		$ 370
Commitment fee rate (as a percentage)	0.25%
Amount outstanding on Revolving Credit Facility	$ 0		$ 0
Letters of credit outstanding	$ 4.8		$ 4.6
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	1.25%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	1.50%
Revolving Credit Facility [Member] | Base Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	0.25%
Revolving Credit Facility [Member] | Base Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	0.50%
ABL Term Loan Due 2025 [Member]
ABL Term Loan [Abstract]
Debt Instrument, Face Amount		$ 50
Debt Instrument, Interest Rate During Period	2.33%
Debt Instrument, Interest Rate During Period With Patronage Credits	1.30%
ABL Term Loan Due 2025 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	1.75%
ABL Term Loan Due 2025 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	2.00%
ABL Term Loan Due 2025 [Member] | Base Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	0.75%
ABL Term Loan Due 2025 [Member] | Base Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	1.00%

Debt_Term Loan (Details)

Debt:Term Loan (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Mar. 30, 2016
Debt Instrument [Line Items]
Repayments of Long-term Debt		$ 405,774	$ 5,500	$ 7,500
Term Loan Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 75,000
Repayments of Long-term Debt	$ 45,000				$ 30,000
Debt Instrument, Interest Rate During Period		2.82%
Debt Instrument, Interest Rate During Period With Patronage Credits		1.80%
Term Loan Due 2026 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.875%
Term Loan Due 2026 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate		2.125%
Term Loan Due 2026 [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate		0.875%
Term Loan Due 2026 [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate		1.125%

Debt_2024 Notes (Details)

Debt:2024 Notes (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Jul. 27, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 29, 2016
Extinguishment of Debt [Line Items]
Loss on Extinguishment of Debt				$ (13,968)	$ 0	$ 0
5.625% Senior Notes Due 2024 [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount	$ 137,500	$ 212,500		350,000
Loss on Extinguishment of Debt			$ (14,000)	(14,000)
Debt extinguishment premiums paid				10,800
Write off of Unamortized Deferred Financing Cost				$ 3,200
5.625% Senior Notes Due 2024 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 350,000
Interest rate							5.625%
4.875% Senior Notes Due 2030 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 400,000
Interest rate		4.875%

Debt_2030 Notes (Details)

Debt:2030 Notes (Details) - USD ($) $ in Thousands	1 Months Ended	5 Months Ended	12 Months Ended
	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
Debt Instrument [Line Items]
Repayments of Long-term Debt			$ 405,774	$ 5,500	$ 7,500
Term Loan Due 2026 [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 45,000					$ 30,000
4.875% Senior Notes Due 2030 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Dividend restriction, interest coverage ratio (as a percent)		350.00%

Debt_Cash Paid for Interest (De

Debt:Cash Paid for Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Interest Paid	$ 22.2	$ 24.1	$ 24.1

Leases Leases_ Costs (Details)

Leases Leases: Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 13,339	$ 13,541
Amortization of right-of-use assets	2,210	1,616
Interest on lease liabilities	2,271	1,899
Variable lease cost	2,967	2,645
Short-term lease cost	4,115	4,614
Sublease income	(140)	(540)
Total lease cost	$ 24,762	$ 23,775

Leases Leases_ Other Informatio

Leases Leases: Other Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Lessee Disclosure [Abstract]
Operating cash flows from operating leases		$ 13,018	$ 13,508
Operating cash flows from finance leases		2,271	1,862
Financing cash flows from finance leases		1,307	783
Right-of-use assets obtained in exchange for lease obligations, operating leases		8,310	4,211
Right-of-use assets obtained in exchange for lease obligations, finance leases		$ 9,969	$ 2,637
Weighted-average remaining lease term (years), operating leases		8 years	8 years
Weighted-average remaining lease term (years), finance leases		15 years	14 years
Weighted average discount rate, percent, operating leases	[1]	6.40%	6.50%
Weighted average discount rate, percent, finance leases		7.70%	8.50%
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021		$ 13,593
2022		13,024
2023		12,073
2024		11,189
2025		9,448
Thereafter		25,545
Total future minimum lease payments		84,872
Less: interest		(18,945)
Total lease obligations		65,927
Long-term lease obligations		56,001	$ 58,029
Finance Lease, Liability, Payment, Due [Abstract]
2021		3,924
2022		3,930
2023		3,970
2024		3,967
2025		3,607
Thereafter		37,801
Total future minimum lease payments		57,199
Less: interest		(24,035)
Total lease obligations		33,164
Long-term lease obligations		31,607	$ 23,419
Lessee, Operating Lease Not Yet Commenced, Future Payments Due		7,300
Other Current Liabilities
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Less: current obligations		(9,926)
Finance Lease, Liability, Payment, Due [Abstract]
Less: current obligations		$ (1,557)
[1]	Upon adoption of the new lease standard, discount rates used for existing leases were established at January 1, 2019.

Leases Leases_Topic 840 Disclos

Leases Leases:Topic 840 Disclosure (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Operating Leases, Rent Expense, Net [Abstract]
Rent Expense	$ 18.2
Buildings [Member]
Property, Plant and Equipment [Line Items]
Lease Obligation Incurred	$ 18.9
Buildings [Member] | Capital Lease 1 [Member]
Property, Plant and Equipment [Line Items]
Lessee, Capital Lease, Term of Contract	13 years
Buildings [Member] | Capital Lease 2 [Member]
Property, Plant and Equipment [Line Items]
Lessee, Capital Lease, Term of Contract	20 years

Defined Benefit Plans (Details)

Defined Benefit Plans (Details) $ in Thousands		Sep. 30, 2019USD ($)	Aug. 10, 2018USD ($)	Apr. 25, 2018USD ($)	Dec. 31, 2020USD ($)Integer7	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Aug. 09, 2018	[6]	Apr. 24, 2018	[6]	Dec. 31, 2018USD ($)	Dec. 31, 2020USD ($)Integer7Integer3		Dec. 31, 2019USD ($)Integer3		Dec. 31, 2018USD ($)Integer3
Defined Benefit Plan Disclosure [Line Items]
Percentage of defined benefit plan assets transferred out of the plan		10.00%																60.00%
Change in Benefit Obligation
Benefit obligation at beginning of year														$ 192,061		$ 176,852
Service cost														668		647		$ 794
Interest cost														5,893		7,210		11,344
Actuarial loss														18,605		29,065
Group annuity transactions	[1]													(76,650)		(19,848)
Benefits paid	[2]													(135,690)		(1,865)
Benefit obligation at end of year					$ 4,887								$ 176,852	4,887		192,061		176,852
Change in plan assets
Fair value of plan assets at beginning of year														168,651		154,801
Actual return on plan assets														30,930		29,769
Employer contributions														12,759		5,238
Group annuity transactions		$ (19,800)	$ (124,800)	$ (151,800)										(76,650)	[1]	(19,292)	[1]
Benefits Paid	[2]													(135,690)		(1,865)
Fair value of plan assets at end of year					0								$ 154,801	0		168,651		154,801
Underfunded status					(4,887)									(4,887)		(23,410)
Amounts recognized on our Conolidated Balance Sheets
Current liabilities					(367)									(367)		(878)
Noncurrent liabilities					(4,520)									(4,520)		(22,532)
Net liability					(4,887)									(4,887)		(23,410)
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss					1,443									1,443		15,332
Prior service cost					0									0		0
Net loss recognized					1,443									1,443		15,332
Accumulated benefit obligation					4,900									4,900		192,100
Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive (Income) Loss
Service cost														668		647		794
Interest cost														5,893		7,210		11,344
Expected return on plan assets														(5,493)		(5,903)		(11,097)
Amortization of actuarial (gain) loss														807		(175)		1,497
Plan settlement expense					$ 6,200	$ 1,300	$ 11,300	$ 12,000						6,250	[3]	1,342	[3]	23,255	[3]
Net periodic benefit cost														8,125		3,121		25,793
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Net actuarial (gain) loss														(6,832)		4,642		(14,178)
Amortization of actuarial gain (loss)	[4]													(807)		175		(1,497)
Effects of settlements	[4]													(6,250)		(1,342)		(23,255)
Total recognized in other comprehensive (income) loss														(13,889)		3,475		(38,930)
Total recognized in net periodic cost and other comprehensive (income) loss														(5,764)		6,596		(13,137)
Plan settlement expense														$ (6,300)		$ (1,300)		$ (23,300)
Weighted Average Assumptions Used in Measurement of Benefit Obligation
Discount rate					2.00%									2.00%		3.10%
Rate of compensation increases	[5]				0.00%									0.00%		0.00%
Weighted Average Assumptions Used in Measurement of Net Periodic Benefit Cost
Discount rate									4.05%		3.40%		3.95%	3.10%		4.15%	[6]
Expected long-term rate of return on plan assets									4.50%		4.75%		3.85%	3.50%		3.85%	[6]
Rate of compensation increases	[5]													0.00%		0.00%		0.00%
Pension Contributions
Number of real property contributed to the qualified defined benefit pension plan | Integer7					4									4
Number of repurchased real property | Integer3														2		1		1
Pension contributions														$ 12,759		$ 5,238		$ 26,081
Estimated Future Contributions
Estimated 2021 contributions					$ 400									400
Expected Future Benefit Payments
2021					367									367
2022					380									380
2023					382									382
2024					368									368
2025					314									314
Years 2026-2030					1,373									1,373
Pension Plan, Repurchases [Member]
Pension Contributions
Pension contributions														11,400		3,600		4,000
Pension Plan [Member]
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Plan settlement expense					$ (6,200)
Pension Contributions
Pension contributions														12,800		5,200		26,100
Pension Plan, Discretionary Contributions [Member]
Pension Contributions
Pension contributions																		20,000
Pension Plan, Lease Payments [Member]
Pension Contributions
Pension contributions														$ 600		$ 1,100		$ 1,500
[1]	See Defined Benefits Plans above for description of group annuity transactions.
[2]	See Defined Benefits Plans above for description of lump-sum payments.
[3]	Plan settlement expense during the years ended December 31, 2020, 2019, and 2018 includes $6.3 million, $1.3 million and $23.3 million, respectively, of settlement charges related to the transfers of pension plan assets to Prudential for the purchase of group annuity contracts, as well as lump-sum payments in 2020.
[4]	Represents amounts reclassified from accumulated other comprehensive loss. These amounts are included in the computation of net periodic pension cost. For additional information, see Note 12, Retirement and Benefit Plans.
[5]	Pension benefits for all salaried employees are frozen, resulting in an assumption for the rate of compensation increase of zero.
[6]	Prior to the remeasurements of our qualified defined benefit pension plan on April 25, 2018, and August 10, 2018, the discount rates were 3.40% and 4.05%, respectively, and the expected rates of return on plan assets were 4.75% and 4.50%, respectively. The discount rate and expected rate of return on plan assets after the August 10, 2018 remeasurement were 3.95% and 3.85%, respectively.

Defined Contribution Plans (Det

Defined Contribution Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percentage of employees' pay	4.00%
Contributions paid	$ 23.4	$ 19.8	$ 22.2
Minimum [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage Contributed for Additional Performance Target	2.00%	1.60%	2.00%
Maximum [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage Contributed for Additional Performance Target	4.00%	3.10%	4.00%

Postretirement Benefit Plans (D

Postretirement Benefit Plans (Details)	5 Months Ended	6 Months Ended	12 Months Ended
	May 31, 2018USD ($)	Nov. 30, 2020USD ($)	Dec. 31, 2020USD ($)employees	May 31, 2020USD ($)	Dec. 31, 2019USD ($)employees	May 31, 2019USD ($)	Dec. 31, 2018USD ($)employees
Multiemployer Defined Contributory Trust Plan [Member]
Multiemployer Plans [Line Items]
Number of employees in plan | employees			735		1,215		1,221
Required employer's contribution per hour per active employee			$ 0.90		$ 0.90		$ 0.85
Required defined contributory trust contribution, percent of earnings.			4.50%		4.50%		4.50%
Period Contributions			$ 2,400,000		$ 2,600,000		$ 2,800,000
Multiemployer Health and Welfare Plan [Member]
Multiemployer Plans [Line Items]
Number of employees in plan | employees					475		604
Required employer's contribution per hour per active employee	$ 6.10	$ 7		$ 6.70		$ 6.40
Period Contributions			$ 5,800,000		$ 6,700,000		$ 7,700,000

Deferred Compensation Plan (Det

Deferred Compensation Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Compensation Plans [Line Items]
Imputed interest rate credited to the Deferred Compensation Plan participant's account as a percentage to Moody's Composite Average of Yields on Corporate Bonds	130.00%
Interest expense	$ 26,223	$ 26,051	$ 26,193
Accrued liabilities compensation and benefits [Member]
Deferred Compensation Plans [Line Items]
Deferred compensation liability	5,900	2,100
Other compensation and benefits [Member]
Deferred Compensation Plans [Line Items]
Deferred compensation liability	19,800	21,600
Deferred compensation arrangement with individual [Member]
Deferred Compensation Plans [Line Items]
Interest expense	$ 1,000	$ 1,100	$ 1,000

Fair Value Measurements of Plan

Fair Value Measurements of Plan Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets		$ 0	$ 168,651	$ 154,801
Receivables and Accrued Expenses, Net, Defined Benefit Plan Assets			$ (240)
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Period of Notice Required to Redeem Investments			1 day
Fixed Income Securities - Russell 14-Year LDI Fixed Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Term of Fund			14 years
Fixed Income Securities - Russell 8-Year LDI Fixed Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Term of Fund		8 years
Fixed Income Securities - Russell STRIPS Fixed Income Funds - Ten Years [Member]
Defined Benefit Plan Disclosure [Line Items]
Term of Fund			10 years
Fixed Income Securities - Russell STRIPS Fixed Income Funds - Fifteen Years [Member]
Defined Benefit Plan Disclosure [Line Items]
Term of Fund			15 years
Fixed Income Securities - Russell STRIPS Fixed Income Funds - Twenty-Eight Years [Member]
Defined Benefit Plan Disclosure [Line Items]
Term of Fund			28 years
Multi-Asset Class Fund - Global Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage			75.00%
Multi-Asset Class Fund - Marketable Real Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage			15.00%
Multi-Asset Class Fund - Global Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage			10.00%
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets			$ 168,891
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[1]		152,530
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Multi-Asset Class Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[2]		16,361
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets			0
Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[1]		0
Level 1 [Member] | Multi-Asset Class Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[2]		0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[3]		168,891
Level 2 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[1],[3]		152,530
Level 2 [Member] | Multi-Asset Class Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[2],[3]		16,361
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets			0
Level 3 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[1]		0
Level 3 [Member] | Multi-Asset Class Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	[2]		$ 0
[1]	Invested in the Russell Long Duration Fixed Income Fund, which is designed to provide current income and capital appreciation through diversified strategies including sector rotation, modest interest rate timing, security selection, and tactical use of high-yield, emerging market bonds and other non-index securities. In addition, our investments in this category included the Russell 14 Year LDI Fixed Income Fund. We also were invested in the Russell 8 Year LDI Fixed Income Fund. These LDI funds invest primarily in investment grade bonds that closely match those found in discount rate curves used to value U.S. pension liabilities and seeks to provide additional incremental return through modest interest rate timing, security selection, and tactical use of non-credit sectors. In addition, our investments in this category included Russell STRIPS Fixed Income Funds with duration profiles of 10, 15, and 28 years. These funds invest in a subset of the STRIPS universe with a similar duration profile as their respective Bloomberg Barclays U.S. STRIPS Index.
[2]	Invested in the Russell Multi-Asset Core Plus Fund, which is designed to provide long-term growth by providing a diversified portfolio of investments that has an overall strategic allocation of 75% global equity, 15% marketable real assets, and 10% global fixed income.
[3]	Securities represent common collective trusts managed and valued by Russell Trust Company, the administrator of the funds. While the underlying assets are actively traded on an exchange, the funds are not. The investments in equity and fixed-income securities are considered to have a readily determinable fair value because the fair value per share (unit) is determined and published and is the basis for current transactions. We had the ability to redeem these securities with a 1 day notice.

Long-Term Incentive Compensat_3

Long-Term Incentive Compensation Plans:Stock-Based Compensation (Details) shares in Millions	12 Months Ended
	Dec. 31, 2020stock_awardsshares	Dec. 31, 2019stock_awards	Dec. 31, 2018stock_awards
Compensation Related Costs [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	3.7
Number of types of stock-based awards granted (in types) | stock_awards	2	2	2
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2.5

Long-Term Incentive Compensat_4

Long-Term Incentive Compensation Plans:PSU and RSU Awards (Details) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2020USD ($)tranch$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Stock-Based Compensation [Abstract]
Fair market value of PSUs and RSUs vested | $		$ 11,100	$ 11,400	$ 15,400
Share-based Compensation Expense | $		7,820	7,973	8,831
Tax benefit from compensation expense | $		2,000	$ 2,000	$ 2,200
Unrecognized compensation expense | $		$ 9,200
Unrecognized Compensation, Period for Recognition		1 year 10 months 24 days
Officer [Member]
Stock-Based Compensation [Abstract]
Performance Shares that could be awarded, as a percentage of ROIC target amount, minimum		0.00%
Performance Shares that could be awarded, as a percentage of ROIC target amount, maximum		200.00%
Performance Shares Target Percentage Earned, ROIC			93.00%	100.00%
Other employees [Member]
Stock-Based Compensation [Abstract]
Performance Shares that could be awarded, as a percentage of target amount, minimum		0.00%
Performance Shares that could be awarded, as a percentage of target amount, maximum		200.00%
Performance Shares Target Percentage Earned, EBITDA			96.00%	110.00%
Number of equal tranches for annual vesting (in tranches) | tranch		3
Performance Shares [Member]
Stock-Based Compensation [Abstract]
Share-based Compensation Expense | $		$ 3,795	$ 3,340	$ 4,005
Number of shares [Abstract]
Outstanding, December 31, 2019 | shares		295,347
Granted | shares		94,850	110,923	78,976
Performance condition adjustment | shares	[1]	(6,989)
Vested | shares		(162,622)
Forfeited | shares		(24,246)
Outstanding, December 31, 2020 | shares		196,340	295,347
Weighted Average Grant Date Fair Value [Abstract]
Outstanding, December 31, 2019 | $ / shares		$ 31.09
Granted | $ / shares		36.45	$ 29.48	$ 43.05
Performance condition adjustment | $ / shares	[1]	29.48
Vested | $ / shares		28.93
Forfeited | $ / shares		32.57
Outstanding, December 31, 2020 | $ / shares		$ 35.34	$ 31.09
Performance Shares [Member] | Officer [Member]
Stock-Based Compensation [Abstract]
Vesting period (in years)		3 years
Performance Shares [Member] | Other employees [Member]
Stock-Based Compensation [Abstract]
Number of equal tranches for annual vesting (in tranches) | tranch		3
Restricted Stock Units (RSUs) [Member]
Stock-Based Compensation [Abstract]
Share-based Compensation Expense | $		$ 4,025	$ 4,633	$ 4,826
Number of shares [Abstract]
Outstanding, December 31, 2019 | shares		257,564
Granted | shares		125,716	167,861	99,087
Performance condition adjustment | shares	[1]	0
Vested | shares		(143,807)
Forfeited | shares		(26,707)
Outstanding, December 31, 2020 | shares		212,766	257,564
Weighted Average Grant Date Fair Value [Abstract]
Outstanding, December 31, 2019 | $ / shares		$ 31.14
Granted | $ / shares		36.45	$ 29.13	$ 43.08
Performance condition adjustment | $ / shares	[1]	0
Vested | $ / shares		30.88
Forfeited | $ / shares		32.82
Outstanding, December 31, 2020 | $ / shares		$ 34.24	$ 31.14
Restricted Stock Units (RSUs) [Member] | Officers and other employees [Member]
Stock-Based Compensation [Abstract]
Number of equal tranches for annual vesting (in tranches) | tranch		3
Restricted Stock Units (RSUs) [Member] | Nonemployee Directors [Member]
Stock-Based Compensation [Abstract]
Vesting period (in years)		1 year
[1]	Represents total PSUs forfeited during the year ended December 31, 2020, related to the 2019 performance condition adjustment described above

Long-Term Incentive Compensat_5

Long-Term Incentive Compensation Plans:Cash Plan (Details) - Other employees [Member] $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)tranch	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Stock-Based Compensation [Abstract]
Performance cash awards that could be awarded, as a percentage of target amount, minimum	0.00%
Performance cash awards that could be awarded, as a percentage of target amount, maximum	200.00%
Number of equal tranches for annual vesting (in tranches) | tranch	3
Performance Cash Awards Target Percentage Earned		96.00%	110.00%
General and Administrative Expense [Member]
Stock-Based Compensation [Abstract]
Long-Term Incentive Cash Plan Expense | $	$ 3.9	$ 2.2	$ 1.4

Stockholders' Equity_Shares and

Stockholders' Equity:Shares and Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 05, 2021	Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020	Mar. 31, 2020		Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019		Dec. 31, 2018	Sep. 30, 2018		Jun. 30, 2018	Mar. 31, 2018		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares authorized		300,000,000							300,000,000												300,000,000	300,000,000
Common stock, shares issued		44,568,299							44,352,778												44,568,299	44,352,778
Common stock, outstanding		39,201,226							38,985,705												39,201,226	38,985,705
Dividends paid on common stock, per share		$ 0.10		$ 1.70	[1]	$ 0.10	$ 0.10		$ 1.10	[2]	$ 0.09	$ 0.09	$ 0.09		$ 0.09	$ 1.07	[2]	$ 0.07	$ 0.07		$ 2	$ 1.37	$ 1.30
Dividends paid on common stock		$ 66,642	[1]	$ 3,991		$ 3,917	$ 4,645	[3]	$ 42,884	[2]	$ 3,508	$ 3,509	$ 4,053	[3]	$ 3,502	$ 41,632	[2]	$ 2,723	$ 2,758	[3]	$ 79,195	$ 53,954	$ 50,615
Supplemental dividend per share declared				$ 1.60					$ 1							$ 1
Supplemental dividend per share paid		$ 1.60							$ 1							1
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, shares authorized		50,000,000							50,000,000												50,000,000	50,000,000
Preferred stock, shares issued		0							0												0	0
Preferred stock, shares outstanding		0							0												0	0
Subsequent Event [Line Items]
Dividends declared per common share		$ 0.10		$ 1.70	[1]	$ 0.10	$ 0.10		$ 1.10	[2]	$ 0.09	$ 0.09	$ 0.09		$ 0.09	$ 1.07	[2]	$ 0.07	$ 0.07		$ 2	$ 1.37	$ 1.30
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared	Feb. 5, 2021
Dividends declared per common share	$ 0.10
Dividends Payable, Date to be Paid	Mar. 15, 2021
Dividends Payable, Date of Record	Feb. 22, 2021
[1]	During third quarter 2020, our board of directors declared a supplemental dividend of $1.60 per share on our common stock, which was paid in fourth quarter 2020.
[2]	During each fourth quarter 2019 and third quarter 2018, our board of directors declared and paid a supplemental dividend of $1.00 per share of our common stock
[3]	Includes payments of dividend equivalents on RSUs and PSUs which vested in first quarter of each year.

Stockholders' Equity_Stock Repu

Stockholders' Equity:Stock Repurchase (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 25, 2015
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method			$ 4,930
Share Repurchase Program 2015 [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased				2,000,000
Treasury stock, shares acquired	0	0	200,000
Treasury Stock, Value, Acquired, Cost Method			$ 4,900
Treasury Stock Acquired, Average Cost Per Share			$ 24.65
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	496,989

Stockholders' Equity_AOCI (Deta

Stockholders' Equity:AOCI (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2020	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance, net of taxes			$ 701,330		$ 672,590	$ 674,549
Net actuarial gain (loss), before taxes			6,832		(4,642)	14,178
Amortization of actuarial (gain) loss, before taxes	[1]		807		(175)	1,497
Effect of settlements, before taxes	[1]		6,250		1,342	23,255
Income taxes			35,281	[2]	879	(9,880)
Ending Balance, net of taxes		$ 850,799	850,799		701,330	672,590
Stranded tax effects of Plan Termination		38,800	38,794	[3]	0	0
Accumulated Other Comprehensive Loss [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance, net of taxes			(50,248)		(47,652)	(76,702)
Ending Balance, net of taxes		$ (1,078)	$ (1,078)		$ (50,248)	$ (47,652)
[1]	Represents amounts reclassified from accumulated other comprehensive loss. These amounts are included in the computation of net periodic pension cost. For additional information, see Note 12, Retirement and Benefit Plans.
[2]	For the year ended December 31, 2020, income taxes include $38.8 million related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes
[3]	In December 2020, we eliminated our qualified defined benefit pension plan (Plan Termination), as discussed in Note 12, Retirement and Benefit Plans. Prior to the Plan Termination, "Accumulated other comprehensive loss" on our Consolidated Balance Sheet included the stranded tax effects of our conversion from a limited liability company to a corporation in 2013 and the adoption of the Tax Cuts and Jobs Act (the "Tax Act") in 2017. Upon Plan Termination, these stranded tax effects of $38.8 million were required to be released into income tax expense under GAAP.

Transactions With Related Par_2

Transactions With Related Party (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unconsolidated variable interest entity [Member]
Related Party Transaction [Line Items]
Revenue from related parties	$ 12.6	$ 16.5	$ 16.7
Cost of sales from related party	$ 70.6	$ 81.7	$ 83.1
Louisiana Timber Procurement Company LLC [Member]
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%
Louisiana Timber Procurement Company LLC [Member] | Packaging Corporation of America (PCA) [Member] | Variable interest entity, primary beneficiary [Member]
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%

Financial Instruments Risk (Det

Financial Instruments Risk (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
Interest Rate Derivatives [Abstract]
Long-term debt		$ 443,792	$ 440,544
Repayments of Long-term Debt		405,774	5,500	$ 7,500
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Other Noncurrent Liabilities [Member]
Interest Rate Derivatives [Abstract]
Fair value of interest swap agreements, Liability		600
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Other Noncurrent Assets [Member]
Interest Rate Derivatives [Abstract]
Fair value of interest rate swap agreements, Asset			$ 800
Interest Rate Swap - $50 million notional amount fixed at 1.007% [Member] | Not Designated as Hedging Instrument [Member]
Interest Rate Derivatives [Abstract]
Interest rate swaps, notional amount		$ 50,000
Interest rate swaps, fixed interest rate		1.007%
Interest Rate Swap - 50 Million Notional Amount Fixed At 0.39% [Member] | Not Designated as Hedging Instrument [Member]
Interest Rate Derivatives [Abstract]
Interest rate swaps, notional amount		$ 50,000
Interest rate swaps, forward interest rate		0.39%
ABL Term Loan Due 2025 [Member]
Interest Rate Derivatives [Abstract]
Long-term debt		$ 50,000
Term Loan Due 2026 [Member]
Interest Rate Derivatives [Abstract]
Repayments of Long-term Debt	$ 45,000				$ 30,000
Notional Principal Amount of Liquidated Derivative Instruments		$ 45,000

Segment Sales to External Custo

Segment Sales to External Customers by Product Line (Details) $ in Thousands		3 Months Ended											12 Months Ended
		Dec. 31, 2020USD ($)	[1]	Sep. 30, 2020USD ($)	[2]	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	[3]	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting [Abstract]
Number of Reportable Segments | segment													2
Sales to external customers [Line Items]
Sales		$ 1,472,200		$ 1,589,300		$ 1,242,800	$ 1,170,500		$ 1,101,700	$ 1,269,500	$ 1,230,100	$ 1,042,100	$ 5,474,838	$ 4,643,404	$ 4,995,290
Wood Products and Building Materials Distribution [Member]
Sales to external customers [Line Items]
Sales													5,474,800	4,643,400	4,995,300
Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												$ 522,800	$ 505,700	$ 707,700
Intersegment EWP Sales Volumes As Percentage to Total EWP Sales Volumes													80.00%	77.00%	74.00%
Building Materials Distribution [Member]
Sales to external customers [Line Items]
Sales													$ 4,952,000	$ 4,137,700	$ 4,287,600
Laminated Veneer Lumber [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												18,400	39,500	42,200
I-joists [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												7,300	22,100	29,300
Other Engineered Wood Products [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												23,900	26,800	25,300
Plywood and veneer [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												332,700	255,100	336,200
Lumber [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												54,700	52,500	86,000	[5]
Byproducts [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												68,600	75,100	87,300
Particleboard [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												0	0	37,500	[5]
Other [Member] | Wood Products [Member]
Sales to external customers [Line Items]
Sales	[4]												17,100	34,700	63,900
Commodity [Member] | Building Materials Distribution [Member]
Sales to external customers [Line Items]
Sales													2,309,900	1,725,400	2,070,100
General line [Member] | Building Materials Distribution [Member]
Sales to external customers [Line Items]
Sales													1,762,300	1,580,700	1,421,500
Engineered wood products [Member] | Building Materials Distribution [Member]
Sales to external customers [Line Items]
Sales													879,900	831,600	796,000
Non-US [Member]
Sales to external customers [Line Items]
Sales													$ 71,000	$ 76,000	$ 96,000
Customer One [Member] | Revenue Benchmark [Member] | Customer Concentration Risk [Member]
Sales to external customers [Line Items]
Concentration Risk, Percentage													11.00%
[1]	Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.
[2]	Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt.
[3]	First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities.
[4]	Amounts represent sales to external customers. Sales are calculated after intersegment sales eliminations to our Building Materials Distribution segment, as well as the cost of EWP rebates and sales allowances provided at various stages of the supply chain (including distributors, retail lumberyards, and homebuilders). For the years ended December 31, 2020, 2019, and 2018, approximately 80%, 77%, and 74%, respectively, of Wood Products' EWP sales volumes were to our Building Materials Distribution segment.
[5]	In fourth quarter 2018, we sold two lumber mills and our particleboard plant located in Northeast Oregon. For additional information, see Note 7, Sale of Manufacturing Facilities.

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended											12 Months Ended
		Dec. 31, 2020		Sep. 30, 2020	[2]	Jun. 30, 2020	Mar. 31, 2020		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information
Sales		$ 1,472,200	[1]	$ 1,589,300		$ 1,242,800	$ 1,170,500	[3]	$ 1,101,700	$ 1,269,500	$ 1,230,100	$ 1,042,100	$ 5,474,838		$ 4,643,404		$ 4,995,290
Income (loss) from operations		99,100	[1]	$ 158,600		$ 51,800	25,500	[3]	24,800	$ 44,900	$ 45,100	$ 21,700	335,029		136,459		72,038
Depreciation and amortization													95,169		80,141		146,837
Capital expenditures													79,429		98,396		105,469
Loss on sale and curtailment of facilities													1,707		0		38,314
Payments to Acquire Businesses, Net of Cash Acquired													0		15,676		25,482
Assets		1,965,718							1,693,351				1,965,718		1,693,351
BMD Birmingham Acquisition [Member]
Segment Reporting Information
Payments to Acquire Businesses, Net of Cash Acquired															15,700
Nashville, Medford, and Cincinnati BMD facilities [Member]
Segment Reporting Information
Payments to Acquire Businesses, Net of Cash Acquired																	25,500
Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Segment Reporting Information
Accelerated depreciation													15,000
Curtailment of LVL Production at Roxboro, NC Facility [Member]
Segment Reporting Information
Accelerated depreciation																	55,000
Operating Segments [Member]
Segment Reporting Information
Income (loss) from operations													375,214		170,433		102,488
Intersegment eliminations [Member]
Segment Reporting Information
Sales	[4]												(801,081)		(769,482)		(825,682)
Corporate, Non-Segment [Member]
Segment Reporting Information
Income (loss) from operations													(40,185)		(33,974)		(30,450)
Depreciation and amortization													1,568		1,701		1,568
Capital expenditures													1,223		4,214		771
Assets		403,182							289,781				403,182		289,781
Wood Products [Member]
Segment Reporting Information
Sales	[5]												522,800		505,700		707,700
Depreciation and amortization													71,141	[6]	57,671		126,989	[6]
Capital expenditures													$ 38,230		$ 53,460		$ 53,392
Intersegment Sales As Percentage to Total Sales													61.00%		60.00%		54.00%
Assets		605,359							635,475				$ 605,359		$ 635,475
Wood Products [Member] | Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Segment Reporting Information
Accelerated depreciation							15,000						15,000
Other closure related costs							$ 1,700						1,700
Wood Products [Member] | Curtailment of LVL Production at Roxboro, NC Facility [Member]
Segment Reporting Information
Accelerated depreciation																	$ 55,000
Accelerated depreciation and other costs																	57,800
Wood Products [Member] | Loss on sale and curtailment of facilities [Member]
Segment Reporting Information
Loss on sale and curtailment of facilities																	35,500
Wood Products [Member] | Operating Segments [Member]
Segment Reporting Information
Sales													1,323,901		1,275,167		1,533,270
Income (loss) from operations													127,720	[7]	54,197		(10,022)	[7]
Building Materials Distribution [Member]
Segment Reporting Information
Sales													4,952,000		4,137,700		4,287,600
Depreciation and amortization													22,460		20,769		18,280
Capital expenditures													39,976		40,722	[8]	51,306	[8]
Assets		$ 957,177							$ 768,095				957,177		768,095
Building Materials Distribution [Member] | Operating Segments [Member]
Segment Reporting Information
Sales													4,952,018		4,137,719		4,287,702
Income (loss) from operations													$ 247,494		$ 116,236		$ 112,510
[1]	Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.
[2]	Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt.
[3]	First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities.
[4]	Primarily represents intersegment sales from our Wood Products segment to our Building Materials Distribution segment. During 2020, 2019, and 2018, approximately 61%, 60%, and 54%, respectively, of Wood Products' overall sales were to our Building Materials Distribution segment.
[5]	Amounts represent sales to external customers. Sales are calculated after intersegment sales eliminations to our Building Materials Distribution segment, as well as the cost of EWP rebates and sales allowances provided at various stages of the supply chain (including distributors, retail lumberyards, and homebuilders). For the years ended December 31, 2020, 2019, and 2018, approximately 80%, 77%, and 74%, respectively, of Wood Products' EWP sales volumes were to our Building Materials Distribution segment.
[6]	Depreciation and amortization for Wood Products includes $15.0 million and $55.0 million, respectively, of accelerated depreciation to fully depreciate the curtailed I-joist and LVL production assets at our Roxboro, North Carolina facility during first quarter 2020 and fourth quarter 2018, respectively. For more information, see Note 6, Curtailment of Manufacturing Facilities.
[7]	Wood Products segment operating income for the year ended December 31, 2020, includes $15.0 million of accelerated depreciation and $1.7 million of other closure-related costs due to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility. In addition, Wood Products segment operating loss for the year ended December 31, 2018, includes pre-tax facility impairment and sales related losses of $35.5 million, as well as $57.8 million of accelerated depreciation and other curtailment costs related to the permanent curtailment of LVL production at our Roxboro, North Carolina facility. For more information, see Note 6, Curtailment of Manufacturing Facilities and Note 7, Sale of Manufacturing Facilities.
[8]	Capital spending in 2019 and 2018 for Building Materials Distribution includes $15.7 million and $25.5 million , respectively, for the acquisition of wholesale building material distribution locations. For more information, see Note 8, Acquisitions.

Commitments, Legal Proceeding_2

Commitments, Legal Proceedings and Contingencies, and Guarantees:Commitments (Details) $ in Millions	Dec. 31, 2020USD ($)
Inventories [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded Unconditional Purchase Obligation	$ 214

Commitments, Legal Proceeding_3

Commitments, Legal Proceedings and Contingencies, and Guarantees:Guarantees (Details) - 4.875% Senior Notes Due 2030 [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Jul. 27, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Long-term Debt, Gross	$ 400,000		$ 0
Senior Notes [Member]
Guarantor Obligations [Line Items]
Long-term Debt, Gross		$ 400,000
Interest rate		4.875%

Quarterly Results of Operatio_3

Quarterly Results of Operations (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended											12 Months Ended
		Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020	Mar. 31, 2020		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales		$ 1,472,200	[1]	$ 1,589,300	[2]	$ 1,242,800	$ 1,170,500	[3]	$ 1,101,700	$ 1,269,500	$ 1,230,100	$ 1,042,100	$ 5,474,838		$ 4,643,404	$ 4,995,290
Income from operations		99,100	[1]	158,600	[2]	51,800	25,500	[3]	24,800	44,900	45,100	21,700	335,029		136,459	72,038
Net income		$ 26,000	[1]	$ 103,200	[2]	$ 33,600	$ 12,200	[3]	$ 14,600	$ 27,200	$ 27,700	$ 11,400	$ 174,979		$ 80,925	$ 20,477
Net income per common share – Basic		$ 0.66	[1]	$ 2.62	[2]	$ 0.85	$ 0.31	[3]	$ 0.37	$ 0.70	$ 0.71	$ 0.29	$ 4.45		$ 2.07	$ 0.53
Net income (loss) per common share – Diluted		$ 0.66	[1]	2.61	[2]	$ 0.85	0.31	[3]	$ 0.37	$ 0.69	$ 0.71	$ 0.29	$ 4.44		$ 2.06	$ 0.52
Loss on Extinguishment of Debt													$ (13,968)		$ 0	$ 0
Plan settlement expense													(6,300)		(1,300)	(23,300)
Stranded Tax Effect of Pension Plan Termination		$ 38,800											38,794	[4]	0	0
Pension Plan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) per common share – Diluted		$ (0.12)
Plan settlement expense		$ (6,200)
Stranded Tax Effects of Plan Termination [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) per common share – Diluted		$ (0.98)
5.625% Senior Notes Due 2024 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) per common share – Diluted				$ (0.27)
Loss on Extinguishment of Debt				$ (14,000)									(14,000)
Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) per common share – Diluted							$ (0.32)
Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accelerated depreciation													15,000
Wood Products [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales	[5]												522,800		$ 505,700	$ 707,700
Wood Products [Member] | Curtailment of I-joist Production at Roxboro, NC Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accelerated depreciation							$ 15,000						15,000
Other closure related costs							$ 1,700						$ 1,700
[1]	Fourth quarter 2020 results include $6.2 million of pre-tax losses, or $0.12 per share after-tax, from a non-cash pension settlement charge related to the Plan Termination, as discussed in Note 12, Retirement and Benefit Plans. Fourth quarter 2020 results also include $38.8 million, or $0.98 per share, of incremental income tax expense related to the release of stranded tax effects upon Plan Termination, as discussed in Note 4, Income Taxes.
[2]	Third quarter 2020 results include $14.0 million of pre-tax losses on extinguishment of debt, or $0.27 per share after-tax, as we refinanced our senior notes at a lower interest rate with an extended maturity, as discussed in Note 10, Debt.
[3]	First quarter 2020 results include $15.0 million and $1.7 million, respectively, of pre-tax accelerated depreciation and other curtailment related costs, or $0.32 per share after-tax, related to the permanent curtailment of I-joist production at our Roxboro, North Carolina facility, as discussed in Note 6, Curtailment of Manufacturing Facilities.
[4]	In December 2020, we eliminated our qualified defined benefit pension plan (Plan Termination), as discussed in Note 12, Retirement and Benefit Plans. Prior to the Plan Termination, "Accumulated other comprehensive loss" on our Consolidated Balance Sheet included the stranded tax effects of our conversion from a limited liability company to a corporation in 2013 and the adoption of the Tax Cuts and Jobs Act (the "Tax Act") in 2017. Upon Plan Termination, these stranded tax effects of $38.8 million were required to be released into income tax expense under GAAP.
[5]	Amounts represent sales to external customers. Sales are calculated after intersegment sales eliminations to our Building Materials Distribution segment, as well as the cost of EWP rebates and sales allowances provided at various stages of the supply chain (including distributors, retail lumberyards, and homebuilders). For the years ended December 31, 2020, 2019, and 2018, approximately 80%, 77%, and 74%, respectively, of Wood Products' EWP sales volumes were to our Building Materials Distribution segment.